Mary, Kurien; Dr.Kuriakose, A P(Cochin University of Science And Technology, September 7, 2002)
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Abstract:
Earlier studies5773 in our laboratory showed that when a nucleophile
is used along with disulphide or sulphenamide accelerators the
vulcanization is accelerated greatly and the reaction mechanism is generally
nucleophilic in nature. However it was observed that it also changes with
the systems under review. The present study, deals with the use of
unsubstituted amidino thiourea i.e. aminoimino methyl thiourea(AMT) V in
the vulcanization studies of different elastorners and their blends. One of the
aims of this study was to get further proof with regard to the
theory of nucleophilic reaction mechanism in such binary systems.Mixes containing thiourea are used as controls. AMT is more nucleophilic
than TU and this is clear from the fact that the fonner can condense with
isothiocynate even in the absence of alkali while TU cannot". Also the
guanidinyl group in AMT can facilitate the polarization of the C=S bond
favouring a nucleophilic reaction
Description:
Department Of Polymer Science And Rubber Technology
Cochin University Of Science And Technology
Shiny,Palaty; Dr.Rani,Joseph(Cochin University of Science And Technology, March , 2002)
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Abstract:
The primary objective of this work is to develop an efficient accelerator system
for low temperature vulcanization of rubbers. Although xanthates are known to act as
accelerators for low temperature vulcanization, a systematic study on the mechanism
of vulcanization, the mechanical properties of the vulcanizates at varying temperatures
of vulcanization, cure characteristics etc are not reported. Further. xanthate based
curing systems are not commonly used because of their chance for premature
vulcanization during processing. The proposed study is to develop a novel accelerator
system for the low temperature vulcanization of rubbers having enough processing
safely. lt is also proposed to develop a method for the prevulcanisation of natural
rubber latex at room temperature.
As already mentioned the manufacture of rubber products at low
temperature will improve its quality and appearance. Also, energy consumption can
be reduced by low temperature vulcanization. in addition, low temperature
vulcanization will be extremely useful in the area of repair of defective products,
since subjecting finished products to high temperatures during the process of repair
will adversely affect the quality of the product. Further. room temperature curing
accelerator systems will find extensive applications in surface coating industries.
Description:
Department of Polymer science & Rubber Technology, Cochin University of Science And Technology