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Comparative results between three protocols for achieving highly exfoliated epoxy-clay nanocomposites

Hutchinson J. M., Shiravand F., Calventus Y., Ferrando F.

Polimery

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2014

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T. 59, nr 9

636--642

EN

Three different methods of fabricating polymer layered silicate (PLS) nanocomposites based upon a tri-functional epoxy resin are compared in respect of the nanostructure and impact energy of the cured nanocomposites. The three methods are designed to maximise the amount of intra-gallery reaction that takes place during cure, and this paper examines separately the effects of: (i) increasing the isothermal cure temperature; (ii) preconditioning the resin/clay mixture; and (iii) incorporating an initiator of homopolymerisation within the clay galleries. It is shown that each of these methods increases the degree of exfoliation in the cured nanocomposite, and that this improved nanostructure correlates also with an increase in the impact energy.

PL

Trzema różnymi metodami wytwarzano nanokompozyty na bazie trójfunkcyjnej żywicy epoksydowej napełnianej warstwowymi glinokrzemianami (PLS). Analizowano ich strukturę i wytrzymałość na uderzenie. Porównano efekt uzyskiwany na drodze: (i) zwiększania temperatury izotermicznej reakcji sieciowania żywicy, (ii) wstępnego kondycjonowania sporządzonej mieszaniny żywicy z glinokrzemianem i (iii) prowadzenia reakcji w obecności inicjatora homopolimeryzacji. Wykazano, że każda z ww. metod prowadzi do wzrostu stopnia eksfoliacji usieciowanych nanokompozytów, a zmiany w strukturze znajdują potwierdzenie w zwiększeniu ich udarności.

2

Utilization of chloroorganic waste by their catalytic copolymerization

Kurta S., Zakrzhevsky A., Kurta M.

Polimery

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2007

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T. 52, nr 1

51-55

EN

A new method, proposed by authors, of utilization of chloroorganic waste accompanying the production of 1,2-dichlorethane consists in alkaline dehydrochlorination of this waste (equations 1-5) and simultaneous copolymerization with the unsaturated hydrocarbons of C5-C9 fraction. At the first stage of the process at ambient temperatures (≤ 50 °C) ionic polymerization and copolymerization of the non-saturated components, take place. Then, at higher temperatures (<50 oC) the free radical homopolymerization and copolymerization of vinyl chloride and vinylidene chloride most probably proceed. As a final product, oligomeric and polymeric resin-like products are formed, which can be recommended for the use as hydroisolating material.

PL

Zaproponowana przez autorów nowa metoda utylizacji odpadów chloroorganicznych towarzyszących produkcji 1,2-dichloroetanu polega na alkalicznym odchlorowodorowaniu tych odpadów (równania 1-5) i jednoczesnej kopolimeryzacji z frakcją nienasyconych węglowodorów C5-C9. W pierwszej fazie procesu, w temperaturze otoczenia (≤ 50 ° C) ma miejsce polimeryzacja jonowa i kopolimeryzacja nienasyconych składników. W temperaturze wyższej (<50 oC), zachodzi prawdopodobnie wolnorodnikowa homopolimeryzacja i kopolimeryzacja chlorku winylu i chlorku winylidenu. W wyniku tych reakcji powstają oligomerowe i polimerowe, podobne do żywic produkty, które mogą być rekomendowane jako materiały hydroizolacyjne.

3

Studies on homo and copolymerizations of long-chained alpha-olefins over metallocene catalysts

Quijada R., Rojas R., Guevara J., Narvaez A., Delfin D., Galland G. B.

Polimery

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2000

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T. 45, nr 5

339-343

EN

Metallocene catalysts, viz., rac-Et(Ind)2ZrCl2, rac-Me2- Si(Ind)2ZrCl2 and Ph2C(Flu)(Cp)ZrCl2, were studied in homopolymerization of 1-octadecene and the first two were used in copolymerization of ethylene with 1-octadecene. They exhibited different activities and rac-Et(Ind)2ZrCl2 was the most active in the homopolymerization carried out at 70°C. At 30°C, the activities were practically identical. In the copolymerization runs, the catalysts were similarly active, and the Et-bridged catalyst was the more active. The copolymers prepared over rac-Me2- Si(Ind)2ZrCl2 were found to have more comonomer incorporated. The composition of copolymerization products was found (13C-NMR) to vary with the catalyst system. DSC thermograms showed poly-1-octadecene prepared over rac-Et(Ind)2ZrCl2 to vary in properties with polymerization temperature (Figs. 3-5). The homopolymer prepared at 70°C showed endotherms at 41°C and 53°C and that prepared at 30°C produced one broader peak at 67°C. With rac-Me2Si(Ind)2ZrCl2, the 70°C homopolymer produced one broader peaks at 41°C and 53°C and the 30°C homopolymer gave peaks at 7°C and 67°C. The two peaks in the homopolymer thermograms appear to be explicable in terms of different structural ordering in various homopolymer domains. As the comonomer concentration in the feed was increased, the molecular weight decreased and otherwise was independent of the type of the metallocene used.