Wyniki wyszukiwania - BazTech

1

Przygotowanie i charakterystyka kompozytowego materiału izolacyjnego nano-MgO/polipropylen do budowy linii przesyłowych prądu stałego ultrawysokiego napięcia

Kang Xuefu, Pei Xudong, An Jianzhen, Liang Daping, Ling Shuqi, Wang Yuping

Przemysł Chemiczny

|

2024

|

T. 103, nr 1

97--103

PL

Nanocząstki MgO (nano-MgO) zostały przygotowane przez wspomagane mikrofalowo kalcynowanie Mg(OH)₂ i wykorzystane do modyfikacji właściwości matrycy polipropylenowej (PP) (zawartość nanocząstek do 2% mas.). Dodatek nano-MgO do matrycy PP zawierającej kopolimer etylen/octan winylu spowodował wzrost jej rezystywności objętościowej z 1,73∙10¹⁴ Ωm do 2,85∙10¹⁴ Ωm, ale miał tylko niewielki wpływ na natężenie pola przebicia materiału. Dodatek nano-MgO spowodował również poprawę makroskopowych właściwości elektrycznych materiałów w porównaniu z czystymi próbkami PP. Po dodaniu 0,5% mas. nano-MgO gęstość ładunku przestrzennego kompozytu PP pozostała niezmieniona na poziomie 0,81 C/m² , a gdy zawartość nano-MgO wynosiła 1% mas., gęstość ładunku przestrzennego była najniższa. Wytrzymałość na rozciąganie i wydłużenie przy zerwaniu kompozytowych materiałów izolacyjnych nano-MgO/PP były nieco niższe niż w przypadku czystego PP, ale ogólny spadek nie był znaczący. Badanie właściwości mechanicznych potwierdziło możliwość zastosowania kompozytowych materiałów izolacyjnych nano-MgO/PP w praktyce przemysłowej.

EN

Nano-MgO particles were prepd. by microwave-assisted calcining Mg(OH)₂ and used for modifying properties of the polypropylene (PP) matrix (nano-MgO content up to 2% by mass). The addn. of nano-MgO to the ethylene/vinyl acetate copolymer-cong. PP matrix, resulted in an increase its volume resistivity form 1.73·10¹⁴ Ωm up to 2.85·10¹⁴ Ωm but had only a small impact on the breakdown field strength of the material. The addn. of nano-MgO resulted also in improving the macroscopic elec. properties of the materials when compared with pure PP samples. When 0.5% by mass nano-MgO was added, the space charge d. of PP composite remained unchanged at 0.81 C/m² , and when the content of nano-MgO was 1% by mass, the space charge density was the lowest. The tensile strength and elongation at break of nano-MgO/PP composite insulation materials were slightly lower than that of pure PP, but the overall decline was not significant. The study on mechanical properties conformed the applicability of the nano-MgO/PP composite insulating materials in the industrial practice.

2

Global migration analysis of reusable food contact packaging exposed to varying microwave power levels and durations

Kałwa Klaudia, Dobosz Laura

Packaging Review

|

2024

|

No. 3

12--19

EN

This paper focuses on the study of specific cases of substance migration from plastic packaging into food, aiming to better understand this phenomenon and assess its potential impact on food quality and safety. The samples consisted of 5 food containers obtained from publicly accessible retail chains. In the case of reusable packaging, in accordance with Commission Regulation (EU) No 10/2011 on plastic materials and articles intended to come into contact with food, and Commission Regulation (EU) 2020/1245 amending and correcting Regulation 10/2011, the overall migration test for reusable products and materials is performed three times on the same sample, each time using a different dose of a food simulant liquid. All containers were made of polypropylene (PP/5) according to the markings on the bottom of the packaging, and were indicated by the manufacturers as suitable for microwave heating and freezing. Therefore, the tests also included trials with the use of microwaves. Consequently, tests were prepared for the first part of the study to account for the impact of microwave treatment on the overall migration of the examined containers into food simulant liquids, and for the second part of the study, in which the overall migration was conducted three times on the same packaging sample.

PL

Niniejsza praca koncentruje się na badaniu specyficznych przypadków migracji substancji z opakowań z tworzyw sztucznych do żywności, co ma na celu lepsze zrozumienie tego zjawiska oraz ocenę jego potencjalnego wpływu na jakość i bezpieczeństwo żywności. Próbki stanowiły 5 pojemników na żywność pozyskanych z ogólnodostępnych sieci handlowych. W przypadku opakowań wielokrotnego użytku zgodnie z Rozporządzeniem Komisji (UE) nr 10/2011 w sprawie materiałów i wyrobów z tworzyw sztucznych przeznaczonych do kontaktu z żywnością oraz Rozporządzeniem Komisji (UE) 2020/1245 w sprawie zmiany i sprostowania Rozporządzenia 10/2011 badanie migracji globalnej wyrobów i materiałów wielokrotnego użytku przeprowadza się trzy razy na tej samej próbce, za każdym razem używając innej dawki płynu modelowego imitującego żywność. Wszystkie pojemnik zgodnie z oznaczeniami na dnie opakowania wykonane były polipropylenu (PP/5) oraz z sugerowaną przez producentów możliwością stosowania ich do podgrzewania mikrofalowego oraz mrożenia. Z tego względu w badaniach zdecydowano się również uwzględnić próby z wykorzystaniem mikrofal. W związku z tym zostały przygotowane próby na I część badań uwzględniając wpływ obróbki mikrofalowej na migrację globalną badanych opakowań do płynów imitujących żywność oraz na II część badań, w której przeprowadzono migrację globalną trzy razy na tej samej próbie opakowania.

3

Wyznaczanie właściwości reologicznych polimerowych kompozytów drzewnych o dużej zawartości drewna na podstawie reometrii kapilarnej. Cz. 2, Badania reometryczne

Nastaj Andrzej, Chmielewski Marcin, Buziak Kamila, Wilczyński Krzysztof

Przemysł Chemiczny

|

2023

|

T. 102, nr 3

295--300

PL

Przedstawiono stan wiedzy i przegląd literatury w zakresie właściwości reologicznych polimerowych kompozytów drzewnych. Poddano dyskusji zagadnienie wyznaczania właściwości reologicznych kompozytów drzewnych na podstawie reometrii kapilarnej. Wskazano na rozległe możliwości reometrii kapilarnej w zakresie wyznaczania nie tylko krzywych płynięcia i krzywych lepkości, ale także badania zjawiska poślizgu, oceny granicy płynięcia, różnic naprężeń normalnych oraz lepkości podłużnej. Poddano dyskusji zagadnienie wpływu poprawek reometrycznych Rabinowitscha, Bagleya i Mooneya na położenie krzywej lepkości względem nieskorygowanej krzywej lepkości.

EN

Rheological studies of polymer-wood composite (WPC) with polypropylene matrix contg. 50 or 70% by mass wood filler were performed. Flow and viscosity curves were detd. at 180, 190 and 200°C, and tests of longitudinal viscosity and yield stress at 190°C were carried out. The tested composites had typical pseudoplastic properties, but yield stress, slip phenomenon and stretching (longitudinal viscosity) were obsd. during the flow. The effect of Rabinowitsch, Bagley and Mooney rheometric corrections on the position of the viscosity curve in relation to the uncorrected viscosity curve was discussed.

4

Preparation of magnesium hydroxide by modifier-directed hydration and its effect on flame retardancy and mechanical properties of polypropylene

Wang Mei Jia, Bai Li Mei, Zhang Meng Ting, Ma Yu Xin, Zhao Liu Cheng, Li Shao Ying

Physicochemical Problems of Mineral Processing

|

2023

|

Vol. 59, iss. 6

art. no. 175706

EN

With the rapid development of the polymer materials industry and the improvement of people's environmental awareness, magnesium hydroxide has been widely used in polymer materials due to its high decomposition temperature, non-toxic smoke suppression, and the advantages of neutralizing harmful gases produced by polymer combustion. However, the conventional preparation methods of magnesium hydroxide exhibit several issues, including high hydrophilicity, elevated polarity, and limited compatibility with polymers. This research proposes an improved method by adding sodium stearate and KH560 modifier, controlling the rate of magnesium oxide and preparing magnesium hydroxide flame retardants using a modifier-directed hydration method. Various characterizations confirmed its morphology, particle size and structure. The magnesium hydroxide exhibits low polarity, small particle size, stable structure and excellent hydrophobicity (with a contact angle of 120.32°, and a free energy of 1.34mN/m). In parallel, the magnesium hydroxide/polypropylene composites demonstrate excellent flame retardancy (LOI of 25%, V-1 grade) and simultaneously enhance the dispersion of magnesium hydroxide within the polypropylene matrix, improving the material's toughness and strength.

5

Thermochemical Degradation of Polypropylene: Energy and Exergy Analysis in a Tubular Reactor

Cruz Jose Nolasco, Hernández Irma Pérez, Villalobo María de Lourdes Castellanos, Henández Angélica Pérez, Ávila Juan José López

Journal of Ecological Engineering

|

2023

|

Vol. 24, nr 5

14--21

EN

One method to evaluate the energy behavior is energy and exergy analysis. These analyses applied to waste-to-energy conversion technologies provide the information on operating conditions, facilitating energy optimization processes. In this study, an energetic and exergy analysis was used on the thermochemical degradation process of polypropylene in a tubular reactor at 600 °C with a speed of 15 °C min-1. The experimental data used in this work were taken from the study by Parku et al. (2020). According to the results, energy efficiencies of up to 43% and exergy efficiencies of 38% were achieved, and it was also observed, according to what was reported, that the products obtained from pyrolysis contain a high calorific value and can be used as alternative fuels.

6

Mechanical Properties of Polypropylene Composites with Different Reinforced Natural Fibers – A Comparative Study

Simamora Pintor, Simanjuntak Josua, Sinulingga Karya, Laksono Andromeda Dwi

Journal of Ecological Engineering

|

2023

|

Vol. 24, nr 7

311--317

EN

Developing environmentally friendly and recyclable natural fiber-reinforced polymer composites has recently attracted researchers’ attention and interest. Herein, a comparative study was conducted to compare the mechanical properties of polypropylene (PP) composites with different natural fiber reinforcement, including palm fiber (Arenga pinnata), rice straw (Oryza sativa), coconut husk (Cocos mucifera), old world forked fern leaves (dicranopteris linearis), and snake plant (Sansevieria trifasciata). This study aimed to compare the influence of the five natural fiber materials on the tensile strength and flexural strength of PP composites. The natural fibers were chemically treated with a 5% NaOH solution for 2.5 hours. In the preparation of composites, polypropylene as the matrix is heated to 300 °C and mixed randomly with natural fibers. The test results indicate that the composite with the highest tensile strength (38% higher than the lowest) and flexural strength (102% higher than the lowest) is obtained using the PP composite with reinforced rice straw fiber. In contrast, the PP composites with palm fiber have the lowest tensile strength (72% from the highest tensile strength) and the lowest flexural strength (UFSmin) (62% from the highest flexural strength) corresponds to the PP composites with coconut fiber. This study revealed that the flexural strength of all composite samples was greater than that of pure PP.

7

Pyrolysis-derived waste polypropylene oils in gas turbine engines: a comprehensive performance and emission study

Suchocki Tomasz Kacper, Kazimierski Paweł, Januszewicz Katarzyna, Lampart Piotr, Klimaszewski Piotr, Witanowski Łukasz

Archives of Thermodynamics

|

2023

|

Vol. 44, no 4

157--183

EN

Addressing the burgeoning issue of polymer waste management and disposal, chemical recycling, specifically the production of highquality oil, presents an enticing solution. This research paper delves into the process of plastic waste pyrolysis, focusing on polypropylene, and thoroughly examines the physico-chemical properties of the resulting pyrolytic oil. The oils, obtained from waste plastic pyrolysis (referred to as WPPO), are then blended with kerosene and utilized as fuel for a gas turbine engine. The primary objective of this investigation is to ascertain how the blend composition influences the performance and emission parameters of the micro gas turbine. In our findings, it was observed that all tested waste plastic pyrolysis blends displayed a trend towards escalating regulated emissions such as nitrogen oxides (NOx) with an average increase of 26% for polypropylene pyrolysis oil (PPO). The emission index (EI) for carbon monoxide (CO) was found to be relatively consistent across all fuel blends tested in this study. Interestingly, when considering the thrust specific fuel consumption (TSFC) within the EI calculation, blends of aviation kerosene and plastic oil showed lower values in comparison to the pure Jet A-1 fuel. Furthermore, an augmentation in the proportion of WPPO in the blends consequently led to an elevation in the exhaust gas temperature (an average increase of 8.7% for PPO). Interestingly, the fuel efficiency of the Jet engine, expressed as TSFC, demonstrated a decrease, with an average reduction of 13.8% observed for PPO.

8

Effect of Composition on Melt Flow and Density of Polypropylene Copolymer/Kaolin Geo-Filler Composites

Zulkifli Zulaikha, Daud Yusrina Mat, Zainal Farah Farhana, Hashim Mohammad Firdaus Abu, Aygörmez Yurdakul

Archives of Metallurgy and Materials

|

2023

|

Vol. 68, iss. 1

369--373

EN

This study examined the effects rheological properties of different composition kaolin and kaolin geo-filler in polypropylene composites. Polypropylene composites with varying composition of kaolin geo-filler 0 wt%, 2 wt%, 4 wt%, 6 wt%, 8 wt%, and 10 wt% was prepared and compared with polypropylene composite with raw kaolin. Kaolin is an aluminosilicate based mineral filler was used to prepare geopolymer paste by combining with alkaline activator solution. The polypropylene composite was compounded using a twin-screw extruder and the melt flow index was determined by a constant weight pressure of 2.16 kg at 230°C in 10 min. Knowing the melt flow index is necessary to predict and control the process, the study has demonstrated that the composition of kaolin filler and kaolin geo-filler affects the melt flow, melt density and surface morphology at varies composition. Composites with kaolin geo-filler have demonstrated high melt flow index process and having better distribution and flow.

9

Flax pomace as a substitute for wood raw material in lignocellulosic composite technology

Lipska Karolina, Goławski Sebastisn

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

|

2023

|

No. 123

86--95

EN

Flax pomace as a substitute for wood raw material in lignocellulosic composite technology. In the present study, composites made from flax seed pomace and PE, PP, PLA and modified starch were subjected quality parameter tests. Density, modulus of rapture (MOR), and modulus of elasticity (MOE) were examined, as well as water absorption and swelling to thickness after 2h and 24 h soaking in water, wettability and surface roughness. Addition of flax to different polymers caused significant changes of parameters but the level of influence of the addition varied between polymers. Although the characteristics of the produced biocomposites have been shown to be in general inferior to pure polymers, efforts should be made to improve these characteristics. Agri-food waste products can be a valuable raw material for the production of new type of biomaterials.

PL

Wytłoki lniane jako substytut surowca drzewnego w technologii kompozytów lingocelulozowych. Kompozyty wykonane z wytłoków z nasion lnu oraz HDPE, PP, PLA i skrobi poddano testom parametrów jakościowych. Zbadano gęstość, wytrzymałość na zginanie i moduł sprężystości, a także nasiąkliwość, zwilżalność i chropowatość powierzchni. Dodatek lnu do różnych polimerów spowodował znaczące zmiany parametrów, ale poziom wpływu dodatku różnił się między polimerami. Chociaż wykazano, że parametry jakościowe wytworzonych biokompozytów są niższe od czystych polimerów, należy podjąć wysiłki w celu poprawy tych właściwości. Produkty uboczne z przetwórstwa rolno-spożywczego mogą być cennym surowcem do produkcji nowych przyjaznych dla środowiska materiałów.

10

Corn pomace as a substitute for wood raw material in lignocellulosic composite technology

Lipska Karolina, Ufnowski Paweł

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

|

2023

|

No. 123

109--117

EN

Corn pomace as a substitute for wood raw material in lignocellulosic composite technology. Composites made from polymers PE, PP, PLA and modified starch with addition of corn pomace were produced and subjected quality parameters test. There were examined such parameters as: density, static bending strenght and modulus of elasticity and also water absorption and thickness swelling after 2 h and 24 h soaking in water, wettability and surface roughness. In general, the addition of corn pomace to polymers caused changes of parameters and through comparing parameters of different composites and control samples it was possible to indicate corn composite variants that occurs to have similar properties to pure polymer samples. Waste products should be seriously considered as a valuable substitute of wood raw material, but characteristics of composites should be improved through further research.

PL

Wytłoki kukurydziane jako substytut surowca drzewnego w technologii kompozytów lingocelulozowych. Wytworzono kompozyty z polimerów HDPE, PP, PLA oraz skrobi modyfikowanej z dodatkiem wytłoków ziaren kukurydzianych i poddano je badaniom parametrów jakościowych. Zbadano takie parametry jak: gęstość, wytrzymałość na zginanie statyczne i moduł sprężystości, a także spęcznienie na grubość oraz nasiąkliwość po 2 i 24 godzinach moczenia w wodzie, zwilżalność i chropowatość powierzchni. Dodatek wytłoków kukurydzianych do polimerów spowodował zmiany parametrów, a poprzez porównanie parametrów różnych kompozytów i próbek kontrolnych możliwe było wskazanie wariantów kompozytów zawierających wytłoki kukurydziane, które mają podobne właściwości do próbek czystego polimeru. Pozostałości produkcyjne przemysłu rolno-spożywczego powinny być brane pod uwagę jako wartościowy substytut surowca drzewnego, jednak parametry ich wytwarzania powinny być zoptymalizowane czemu służyć będą dalsze badania.

11

The influence of calcium carbonate and its modifications on the extrusion process and selected properties of polypropylene cast films

Kloziński Arkadiusz, Szczepańska Małgorzata, Jakubowska Paulina, Samujło Bronisław, Barczewski Mateusz, Lota Grzegorz

Polimery

|

2022

|

Vol. 67, nr 10

509--521

EN

The effect of unmodified and stearic acid-modified calcium carbonate (5, 10, 20 and 30 wt%) on selected properties (tensile strength, puncture resistance, haze and gloss) and processability of polypropylene films (MVR, extensional viscosity) was investigated. The composites were obtained in the twin-screw extrusion process with cold granulation, and the films in the single-screw extrusion process, using a flat die head (so-called cast films) and a chill roll type cooling and pull-back device. It has been shown that stearic acid is an effective modifier of polypropylene processing properties both under shear and tensile flow conditions (lower extensional viscosity of films containing modified calcium carbonate).

PL

Zbadano wpływ dodatku 5, 10, 20 oraz 30 % mas. niemodyfikowanego imodyfikowanego kwasem stearynowym węglanu wapnia na wybrane właściwości użytkowe (wytrzymałość na rozciąganie, odporność na przebicie, zamglenie, połysk) iprzetwórcze folii polipropylenowych (MVR, lepkość wzdłużna). Kompozyty otrzymano w procesie dwuślimakowego wytłaczania z granulacją na zimno, a folie w procesie jednoślimakowego wytłaczania, przy użyciu głowicy płaskiej (tzw. cast films) oraz urządzenia chłodząco - odciągającego typu chill roll. Wykazano, że kwas stearynowy jest efektywnym modyfikatorem właściwości przetwórczych folii polipropylenowych zarówno w warunkach przepływu ścinającego, jak i rozciągającego (mniejsza lepkość wzdłużna folii zawierających modyfikowany węglan wapnia).

12

The influence of accelerated aging on selected mechanical properties of polypropylene with organic fillers

Szymiczek Małgorzata, Chomiak Monika, Chmielnicki Błażej, Sarraj Sara, Gołuch Paulina

Polimery

|

2022

|

Vol. 67, nr 7-8

308--316

EN

The aging effect in water atthe temperature of 100±2°C on selected mechanical properties of polypropylene with organic fillers (hemp chaff, a mixture of oak, birch and maple leaves) was investigated. A significant influence of the aging process on the impact strength and elongation at break was observed. The degradation processes were also visible on the surface of the samples.

PL

Zbadano wpływ starzenia w wodzie w temperaturze 100±2°C na wybrane właściwości mechaniczne polipropylenu z napełniaczami organicznymi (plewy konopne, mieszanina liści dębu, brzozy i klonu). Stwierdzono istotny wpływ procesu starzenia na udarność i wydłużenie względne przy zerwaniu. Procesy degradacji widoczne były również na powierzchni próbek.

13

Technology of Utilization of Polypropylene Waste and Wastewater Sediments by Production of Building Blocks

Levytska Olena, Trus Inna, Gomelya Mukola, Alekseyenko Sergey

Ecological Engineering & Environmental Technology

|

2022

|

Vol. 23, iss. 2

50--59

EN

Plastic waste and wastewater sediment stored on sludge lagoons are generated in almost every city in Ukraine. Their disposal is an urgent issue nowadays. The paper shows the ways of polypropylene utilization as one of the most widely used thermoplastics in everyday life, as well as the problem of formation and storage of wastewater sediments. The proposed technological scheme of complex processing of the resulted waste by production of building blocks is based on the property of polypropylene as a thermoplastic to soften and melt at above 160 °C, while exhibiting adhesive properties to a number of materials. For the implementation of technological solutions for manufacturing of construction products, the adhesion properties of polypropylene to wastewater sediments were substantiated, heating modes of the raw material mixture of wastewater sediments and polypropylene waste were specified, and the ratio of raw materials in the mixture for thermal treatment was determined. The samples of building blocks with a mass content of wastewater sediment from 5 to 95% (dry weight sediments) were made in the laboratory. In these samples, the polypropylene content was reduced from 95 to 5%, respectively. It was experimentally determined that for the samples of construction materials with a mass content of wastewater sediment 40–50% (dry weight), a uniform distribution of raw materials that would ensure their high strength, was observed. The comparison of the qualitative characteristics of the samples of building blocks with the regulatory requirements for construction products revealed that the experimental samples met the current requirements and were not inferior to the counterparts from traditional raw materials. However, the construction materials made from waste are recommended for application in building of industrial warehouses and storage facilities, non-food storage chambers, garages or other structures that do not provide permanent storage of food or living place for humans or animals.

14

Selected properties of polypropylene-TiO2 composites after exposure to UV rays – preliminary study

Olesik Piotr, Peryt Aleksander, Stępień Krzysztof, Frączek Violetta, Mackiewicz Krzysztof, Molka Weronika, Musiał Oliwia, Różańska Weronika, Jesionek Marcin

Composites Theory and Practice

|

2022

|

R. 22, nr 1

21--24

EN

In this study the mechanical properties of polypropylene (PP) with a small amount of TiO2, after UV-C exposure were preliminarily analyzed. The effectiveness of titanium oxide was evaluated in two alternative applications: TiO2 as the polymer filler and TiO2 as a protective outer coating. The samples were exposed to UV-C rays for 1000 hours. It was found that an addition of 5 wt.% TiO2 to PP matrix results in a 60% smaller decrease in Rg after 1000 h of exposure to UV-C than in the case of neat polypropylene. It was also found that the addition of TiO2 to the polypropylene matrix is more effective than TiO2 applied as a coating component. The Rg decrease after exposure is about 35% in this case. The research confirmed that TiO2 submicrometric particles seem to be a very good component in reducing the sustainability of polypropylene to UV radiation.

15

Selected properties of polypropylene-BaSO4 composites after UV exposure

Olesik Piotr, Stępień Krzysztof, Peryt Aleksander, Siejka Piotr, Waluś Szymon, Witczak Karolina, Wójcik Weronika, Wolanin Anna

Composites Theory and Practice

|

2022

|

R. 22, nr 1

50--53

EN

The paper presents a preliminary study on the effect of an addition of barium sulfate (BaSO4) particles on the mechanical properties of polypropylene (PP) and an evaluation of the effectiveness of this additive in protecting the material against UV rays. Tests were carried on PP samples filled with BaSO4 powder and on samples covered with a protective coating based on BaSO4. Samples of the materials were exposed to UV-C rays for 1000 hours. After exposure, specimens were subjected to static three-point bending tests and hardness examination. Based on the obtained results, it was concluded that BaSO4 reduces the decrease in flexural strength and in hardness caused by exposure to UV-C rays by half in comparison with neat PP. The action of BaSO4 particles as a filler of PP and as a component of a coating applied on the surface of the sample results in similar anti-UV protection of the material. BaSO4 seems to be a commonly available and inexpensive anti-UV protector for plastics.

16

Optimization of laser cutting conditions of polypropylene and polypropylene with talc

Cienka Agnieszka Edyta, Ciecińska Barbara

Physics for Economy

|

2021

|

Vol. 4

5-15

EN

Laser cutting of materials requires the execution of processing tests and the selection of the most favourable variant from the point of view of the adopted criteria of process quality assessment. This paper presents the example of a preparatory process, which shows that cutting polypropylene and polypropylene with 5 mm thick talc is not an easy process of material handling. A CO2 laser was used and by varying the utilized power from the laser and the beam speed relative to the material, cuts of varying quality were obtained. Criteria were also proposed for the selection of the best processing variant. It was concluded that the addition of talc to polypropylene can be a factor facilitating laser cutting of this material.

17

GC investigation of post-irradiation oxidation phenomena on polypropylene

Głuszewski Wojciech

Nukleonika

|

2021

|

Vol. 66, No. 4

187--192

EN

The paper summarizes the results of research on gas products of polypropylene (PP) radiolysis. Particular attention was paid to the phenomena of post-radiation degradation of PP. The protective effect of selected aromatic compounds was investigated. The research was carried out both from the point of view of obtaining radiation-resistant PP varieties and the possibility of accelerating biodegradation phenomena, e.g., PP/cellulose composition. The phenomena of post-radiation chain oxidation of PP were investigated by gas chromatography (GC). The GC in the system used (packed column, thermal conductivity detector, argon – carrier gas) enables the determination of H2, O2, CO, and CH4 in one measurement. The samples were irradiated with electron beams (EBs) accelerated in accelerators: Elektronika 10/10 with a power of 10 kW and energy of 10 MeV and LAE 13/9 with a power of 9 kW and energy up to 13 MeV. In the tests, PP without stabilizing additives (obtained directly from the production line) and non-stabilized styrene were used. Radiolytic efficiency of hydrogen evolution allowed us to estimate the number of originally formed free radicals. The maintenance of the secondary oxidation processes was the loss of oxygen and the formation of oxidation products (CO, CH4). Attention is paid to the protective effect of aromatic compounds (polystyrene (PS), polyethylene terephthalate (PET), anthracene, fluoranthene, acenaphthene, pyrene, naphthalene) both at the stage of hydrogen atom separation and the secondary oxidation process. The examples of post-radiation oxidation of PP irradiated in cryogenic conditions (–196°C) are presented. All used aromatic compounds showed a protective effect in PP radiolysis. We suppose that this phenomenon is responsible for the charge transfer along the polymer chain from the ionization spurs to the aromatic compound. The protective ranges of PS in PP radiolysis were estimated for the variously prepared PP/PS type compositions from 6 mers to 28 mers.

18

Characteristic of polypropylene nanocomposite material reinforcement with hydroxyapatite for bone replacement

Obaid M. N., Sabr O. H., Hussein A. A.

Journal of Achievements in Materials and Manufacturing Engineering

|

2021

|

Vol. 104, nr 1

21--30

EN

Purpose: Human bone suffered some degeneration due to age and accidents; therefore, there are many interests in the prepared synthetic bone with properties nearer to natural bone. The present study prepared a nanocomposite of polypropylene reinforced with different weight fraction of Nano hydroxyapatite (HAp) to be used as a bone replacement with good biological properties that enhanced the growth of osteoplastic cells and enhance the prevention of clots and coagulates creation. Design/methodology/approach: Nanocomposite from polypropylene reinforced with different weight fraction of Hydroxyapatite (HAp) (1,2 and 3) % prepared by first dispersion Nano hydroxyapatite insolvent and then mixing with a pellet of polypropylene by the twin-screw extrusion process, the current research study the surface properties ( atomic force microscopy (AFM), contact angle test) Moreover, it studied the characteristics of prepared nanocomposite materials (Differential Scanning Calorimetry (DSC), Field Emission-Scanning Electron Microscopy (FE-SEM) and Fourier Transform Infrared (FTIR)). Findings: The AFM results show the surface roughness decreased with increasing content of HAp, which diminished the chance of creation clots and coagulates on it. The contact angle results referred to polypropylene behaviour transformed from hydrophobic to hydrophilic with addition HAp that permission to grow the osteoplastic cell on it, so the healing process is accelerated. Moreover, the FE-SEM images revealed uniform distribution and good bonding between polypropylene and Hydroxyapatite. The thermal properties were measured by the DSC test showed the melting temperature, and the enthalpy of melting (indicated to increase the crystalline structure per cent) are increased with increasing the percentage of Hydroxyapatite. Research limitations/implications: This research studied the characteristics of nanocomposite materials prepared by three steps (dispersion by ultrasonic device, manually mixed and melting and mixing by twin extruder) which can be used as a bone replacement. However, the main limitation was the uniform distribution of nano-hydroxyapatite within the matrix. In a further study, the cytotoxic test can be tested to study the effect of prepared nanocomposite on living cells’ growth. Practical implications: The interest object is how to connect among different properties to prepared bone replacement with good properties and biocompatibility that made able to stimulate the growth and healing process. Originality/value: The nano-hydroxyapatite is a biomaterial that has a composition similar to the natural mineral phase of the bone and does not have any negative effect, which enhanced the growth of osteoplastic cells and decreased the clots and coagulates creation; therefore, nano-hydroxyapatite is used to decrease the surface roughness which decreased the chance of coagulation creation and to enhance the hydrophilic properties.

19

Impact of Activator Content on the Process of Photodegradation of PP Non-Wovens

Mielicka Elżbieta, Witkowska Beata, Puchowicz Dorota, Kamińska Irena

Fibres & Textiles in Eastern Europe

|

2021

|

Vol. 29, no. 3 (147)

47--59

EN

The paper presents the test results of non-wovens modified by an activator in different concentrations, produced by the spun bonding method. The aim of the research was to assess the photodegradation process of modified PP non-wovens in dependence on the selected concentration of the modifying agent in the fibre mass and the possibility of introducing a new range of PP non-wovens in agriculture. Non-wovens having a mass per unit area of 100 g/m2 were exposed to sunlight during its highest intensity for a period of four months, and UV irradiance was tested in a xenon lamp with radiation doses corresponding to exposure to sunlight. The samples were exposed to the same energy value of visible and UV radiation in a given series of exposure. For the variants of non-wovens tested, the tensile strength and mass per unit area were tested and the surface topography of the non-wovens analysed. Microscopic analysis of fibre damage in the modified non-wovens was carried out after different degrees of exposure to light. It was observed that PP non-woven samples exposed outdoors degraded more intensively than those tested in the Xenotest.

PL

Praca przedstawia wyniki badań włóknin, modyfikowanych aktywatorem o różnym stężeniu, wytworzonych metodą spun bonded. Włókniny o masie powierzchniowej 100 g/m2 poddano ekspozycji na światło słoneczne w okresie największego natężenia słońca przez okres czterech miesięcy. Równolegle prowadzono badania natężenia promieniowania UV w lampie xenonowej. Próbki otrzymały jednakową wartość energii promieniowania widzialnego i UV w danej serii naświetlania. Dla badanych wariantów włóknin wykonano badania wytrzymałości na rozciąganie, masy powierzchniowej oraz dokonano analizy topografii powierzchni włóknin. Przeprowadzono analizę mikroskopową uszkodzeń włókien modyfikowanej włókniny po różnym stopniu naświetlenia.

20

Macro- and micromechanical response of glass fibre-reinforced polypropylene to pigmental impurities

Sikorski Ryszard

Composites Theory and Practice

|

2021

|

R. 21, nr 1-2

22--28

EN

The present study investigates the influence of pigmental impurities on glass fibre-reinforced polypropylene using model compounds to simulate the behaviour of recyclate-based compositions. Most industrial-quality (containing recyclate) PP compounds are black coloured (using carbon black pigment), with an almost unavoidable presence of inorganic white pigment (e.g. titanium dioxide) impurities. There are widespread beliefs in the compounding industry that such impurities have a detrimental effect on the mechanical properties of glass fibre-reinforced compounds, but up to now no systematic study of this problem from the industrial point of view has been reported. For this purpose, a range of compounds was prepared on a twin- screw compounding line and the properties were evaluated, with special focus on the mechanical properties. The results confirmed the strong influence of some white pigments, particularly titanium dioxide, and rejected the thesis of the detrimental action of carbon black.