Time controlled photo-oxidation of polyolefins by polymer bound additives

مرکز و کتابخانه مطالعات اسلامی به زبان های اروپایی

منو

" Time controlled photo-oxidation of polyolefins by polymer bound additives "
Islam, Shahida

Document Type	:	Latin Dissertation
Record Number	:	808929
Doc. No	:	TLets357330
Main Entry	:	Islam, Shahida
Title & Author	:	Time controlled photo-oxidation of polyolefins by polymer bound additives\ Islam, Shahida
College	:	University of Aston in Birmingham
Date	:	1992
student score	:	1992
Degree	:	Thesis (Ph.D.)
Abstract	:	A variety of iron compounds containing vinyl or thiol functional groups (used as photoactivators) have been synthesised and some of these were successfully bound to both polyethylene and polypropylene backbones during processing in the presence of peroxide and interlinking agent. Concentrates (masterbatches) of the photoactivators in PP and PE were prepared and the pro-oxidant effect of the diluted masterbatches in absence and presence of an antioxidant was evaluated. An antioxidant photoactivator (FeDNC ) was found to sensitise the photoactivity of pro-oxidants (Metone A / Metone M) whereas an antioxidant (ZnDNC) was found to stabilise the polymer (PP and PE) containing both of these combinations. It was observed that the lower concentration of FeDNC sensitises the stability of the polymer containing very small concentration of NiDNC whereas higher concentration of FeDNC stabilises the polymer (LDPE) containing same amount of NiDNC compared to FeDNC alone. The photostability of unstabilised PP containing FeAc could be varied by varying the concentration of ZnDEC. Both the induction period and the UV - life time of the polymer increased by increasing concentration of ZnDEC. It is suggested that ligand exchange reaction may take place between FeAc and ZnDNC. A polymer bound UV stabiliser (HAEB) and a thermal stabiliser (DBBA) were used with a non extractable photoactivator (FeAc) in PP. Small concentrations of the stabilisers (HAEB and DBBA) in combination with the photoactivator (FeAc) sensitise the polymer. The antioxidant present in commercial polymer (LDPE and PP) was found to be of a hindered phenol type, which was found to antagonise with ZnDNC when used in combination with the photoactivators.
Subject	:	Applied Chemistry; Chemical Engineering
Added Entry	:	Aston University