Abstract: A method of modifying polyolefin to have long chain branching comprising mixing polyolefin and a photoinitiator and irradiating the mixture with UV radiation. The modified polyolefin of the method and the use of said modified polyolefin.

Abstract: A method of modifying polyolefin to have long chain branching comprising mixing polyolefin and a photoinitiator and irradiating the mixture with UV radiation. The modified polyolefin of the method and the use of said modified polyolefin.

Abstract: Branched copolymers of polypropylene (PP) and polysilanes are prepared by procedures involving melt phase hydrosilylation. Such branched copolymers may be formed in situ during the melt phase hydrosilylation or may be prepared by subsequent processing. The branched copolymers exhibit superior properties.

Abstract: A method of modifying crosslinked rubber comprising subjecting the rubber to mechanical elongational and shear forces in the presence of a supercritical fluid that is normally gaseous. Controllable devulcanization of the rubber is achieved.

Abstract: A method of modifying crosslinked rubber comprising subjecting the rubber to mechanical elongational and shear forces in the presence of a supercritical fluid that is normally gaseous. Controllable devulcanization of the rubber is achieved.

Abstract: The hydrosilylation of terminal double bonds in polypropylene (PP) or other polymers is effected in the melt phase. The double bonds were created by peroxide initiated degradation of PP in an extruder or a batch mixer. A hydride terminated polydimethylsiloxane is employed as a model substance to investigate the feasibility of hydrosilylating the terminal double bonds of the degraded polypropylene. The reaction may be carried out in three different reactors, namely a hot press, a batch mixer and a screw extruder. Two different reaction mechanisms may be used to effect the hydrosilylation reaction, namely a radical chain addition mechanism and a platinum catalysed mechanism with a colloid forming catalyst, platinum divinyltetramethyldisiloxane (Karstedt's catalyst). Catalytic amounts of a peroxide initiator are able to initiate the addition of silanes to the double bonds of the degraded polypropylene. Both reactions, namely degradation and hydrosilylation, may be performed simultanously.

Abstract: The surface roughness of an extruded polymeric material is determined by forming a digital image of the extruded surface of the polymeric material and then determining the fractal dimension of any surface distortions of the extruded surface from the digital image. The fractal dimension is a measure of surface roughness and is dimensionless. A value of one indicates a smooth surface, while higher values indicated degrees of roughness. This information may be used to adjust molding conditions to avoid the formation of surface roughness.