Wyniki wyszukiwania - BazTech

1

Influence of an Increased Controlled Dose of Irradiance on the Change of Selected Physicochemical Properties of Paint Systems Used in Rolling Stock

Garbacz Marcin

Problemy Kolejnictwa

|

2022

|

Z. 197

99--115

EN

The article presents the results of ageing tests with the use of laboratory light radiation tested according to the EN ISO 16474-2 standard for painting systems used in rolling stock. The influence of aging on such properties as gloss, colour and hardness, was determined using two different irradiance settings of the order of 60 W/m2 and 120 W/m2 for the wavelength 300÷400 nm and the same levels of radiant exposure. In addition, this study describes the most important information about laboratory aging tests with simulation of sunlight, temperature, moisture including rain, which are included in ISO standardised test methods. The influence of weather parameters has been described, in particular the influence of an increased dose of irradiance on the degradation of selected physicochemical properties of coatings and the possibility of the predicted ageing progress (changes in selected properties). The obtained results of laboratory tests allow to make certain assumptions regarding the increase of the dose of irradiance and thus the shortening of the laboratory testing time in the context of the assessment of the most desirable properties of the coating for a given application with the use of laboratory ageing tests.

2

Influence of accelerated weathering on mechanical and thermomechanical properties of poly(lactic acid) composites with natural waste filler

Barczewski Mateusz, Andrzejewski Jacek, Matykiewicz Danuta, Krygier Agnieszka, Kloziński Arkadiusz

Polimery

|

2019

|

T. 64, nr 2

119--126

EN

In this study we investigated the impact of accelerated weathering on selected mechanical and thermomechanical properties of poly(lactic acid) (PLA) composites filled with ground chestnut shell (CN). The mechanical properties were evaluated through static tensile test and Dynstat impact test, which were conducted for pure PLA and composites containing various amounts of the lignocellulosic organic filler (2.5–30 wt %). The results of the dynamic thermomechanical analysis (DMTA) are discussed in reference to structural changes obtained by differential scanning calorimetry (DSC), and they confirm changes in crystalline structure of PLA and its composites induced by cyclic temperature changes and UV light exposure. Scanning electron microscopy (SEM) images showed presence of microcracks and erosion of the PLA and composite surface after the aging process.

PL

Przedstawiono wpływ przyspieszonego starzenia na wybrane właściwości mechaniczne oraz termomechaniczne kompozytów na osnowie polilaktydu (PLA) modyfikowanego rozdrobnionymi łupinami kasztana (CN). Właściwości mechaniczne kompozytów zawierających 2,5–30 % mas. napełniacza naturalnego oceniano w próbie statycznego rozciągania oraz na podstawie pomiarów udarności metodą Dynstat. Zmiany właściwości niemodyfikowanego PLA oraz jego kompozytów odniesiono do właściwości termomechanicznych ocenianych metodą dynamiczno-mechanicznej analizy termicznej (DMTA) oraz różnicowej kalorymetrii skaningowej (DSC). Zastosowanie wielokryterialnej oceny zmiany właściwości kompozytów, spowodowanej przyspieszonym starzeniem, pozwoliło na stwierdzenie istotnych modyfikacji struktury krystalicznej osnowy polimerowej pod wpływem ekspozycji na światło UV oraz dynamicznych zmian temperatury i wilgotności powietrza. Powierzchnie starzonych próbek materiałowych obserwowano z zastosowaniem skaningowej mikroskopii elektronowej (SEM).

3

Effect of sodium ascorbate on weathering performance of NaOH pulping and paper

Gencer A., Onat S. M., Can A., Ozgul U., Sivrikaya H., Yurdakurban F.

Drewno : prace naukowe, doniesienia, komunikaty

|

2016

|

vol. 59, nr 198

49--60

EN

This study aimed to decelerate the weathering of paper from light by utilizing the antioxidant property of sodium ascorbate (SA), which is an ascorbic acid salt. Three different sessions of cooking were carried out by adding 2.5%, 5.0% and 7.5% of SA in proportion to the weight of a completely dried chip in addition to 24% NaOH in order to identify the influence of SA on cooking. It was observed that the pulp yield decreased when SA was added to the cooking. For that reason, it was decided to add SA into the control pulps instead of adding the digester. The same amount of SA was added to the control. The SA-added pulps were held in the agitator initially first for 2 hours and then 12 hours before making paper. So as to determine the influence of the treatment on the process. The paper was treated for 72, 144 and 256 hours and values of ΔL, Δa, Δb and ΔE were identified in order to determine the period of the SA’s efficacy against weathering. The total discoloration in all the samples of paper, displayed an increase with an extension of the time period. The lowest discoloration after a 256-hour time period was seen in the sample group where 7.5% of SA was added and soaked in the water. The final results indicated that the most appropriate concentration was 5% and that pulp suspension must be retained for 12 hours to improve mechanical properties.

4

Wpływ warunków przyspieszonego starzenia-promieniowania UV oraz temperatury na poliamidy i polipropylen

Brzozowska-Stanuch A., Rabiej S., Stanuch W.

Czasopismo Techniczne. Mechanika

|

2009

|

R. 106, z. 1-M

43-49

PL

Praca zawiera wyniki badań wpływu promieniowania UV oraz temperatury na strukturę cząsteczkową wybranych materiałów polimerowych. Przyspieszone starzenie poliamidów oraz polipropylenu prowadzono przy użyciu komory klimatycznej Atlas Xsenon Weather Ometer serii Ci4000, stosując jako źródło promieniowania filtrowaną lampę ksenonową. Zachodzące zmiany w czasie procesu fotoutleniania monitorowano za pomocą metod FTIR i DSC. W badanych próbkach nastąpiły wyraźne zmiany w obszarach grup: hydroksylowej, karbonylowej a także w obszarze pasm krystalicznych poliamidów.

EN

In this work, the influence of UV radiation and temperature on the molecular structure of chosen polymeric materials was investigated . Accelerated weathering of polyamides and polypropylene was performed by means of the Atlas Xsenon Weather Ometer series Ci4000 climatic chamber, using filtered xenon lamp as a light source. The effects of photo-oxidation were studied by FTIR spectroscopy and DSC method . A clear changes were observed in the investigated samples in hydroxyl and carbonyl regions as well as in the crystalline regions of polyamide