Showing papers by "Universiti Teknologi Petronas published in 2003"
TL;DR: In this article, a fixed bed micro-reactor operated at atmospheric pressure, reaction temperature of 723 K and weight hourly space velocity (WHSV) of 2.5 h−1 over the synthesized mesoporous molecular sieve MCM-41 materials.
123 citations
01 Apr 2003-Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms
TL;DR: The effects of electron beam irradiation on two partially fluorinated polymer films (PVDF and ETFE) are studied at doses ranging from 100 to 1200 kGy in air at room temperature Chemical structure, thermal and mechanical properties of irradiated films are investigated.
Abstract: The effects of electron beam irradiation on two partially fluorinated polymer films ie poly(vinylidene fluoride) (PVDF) and poly(ethylene-tetrafluoroethylene) copolymer (ETFE) are studied at doses ranging from 100 to 1200 kGy in air at room temperature Chemical structure, thermal and mechanical properties of irradiated films are investigated FTIR show that both PVDF and ETFE films undergo similar changes in their chemical structures including the formation of carbonyl groups and double bonding The changes in melting and crystallisation temperatures ( T m and T c ) in both irradiated films are functions of irradiation dose and reflect the disorder in the chemical structure caused by the competition between crosslinking and chain scission The heat of melting (Δ H m ) and the degree of crystallinity ( X c ) of PVDF films show no significant changes with the dose increase, whereas those of ETFE films are reduced rapidly after the first 100 kGy The tensile strength of PVDF films is improved by irradiation compared to its rapid deterioration in ETFE films, which stemmed from the degradation prompted by the presence of radiation sensitive tetrafluoroethylene (TFE) comonomer units The elongation at break of both films drops gradually with the dose increase indicating the formation of predominant crosslinked structures at high doses However, the response of each polymer to crosslinking and main chain scission at various irradiation doses varies from PVDF to ETFE films
76 citations