Polymerisation Size reduction

The important point is that the cellulose in these alum/rosin sized papers is susceptible to acid hydrolysis, which results in a lowering of the degree of polymerisation and, eventually, to a serious reduction in the strength of fibres and to complete embrittlement of the paper. Some recent work in the writer s laboratory suggests that when alum/rosin papers are made, the hydroxonium ions which lead to the degradation are adsorbed independently of aluminium ionic species (4). 

A similar dependency of catalyst dispersity can be observed in another microheterogeneous catalytic system based on the VOCl3-Al(i-C4H9)3 compound, which is widely used in isoprene and butadiene polymerisation processes. A substantial change of particle size in a two-component (V-Al) catalytic system, and the hydrodynamic impact on a catalytic system in a turbulent mode, is not observed with traditional process technology. A substantial decrease of catalyst particle size is observed after modification of the V-Al catalyst using piperylene additives. The hydrodynamic impact on the modified catalytic system results in an additional reduction of catalyst particle size. In addition, the particle size distribution for the Ti-Al catalyst narrows as it does for the V-Al catalyst. 

Biodegradable fumarate-based polyHIPEs synthesised from propylene fumarate dimethaciylate have been investigated as injectable scaffolds for the repair of critical sized bone defects. Culture of NIH/3T3 fibroblasts on such polyHIPEs yielded 95% viability after 24 h. Switching from a thermally initiated curing system to redox initiation resulted in a reduction of the polymerisation time. HIPEs with either a reductant or an oxidant could be... 

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