Inorganics Modification And The Application In PP

Polypropylene (PP) has low relatively density, low price and well processing property. But there are also a lot of shortcomings,such as low temperature brittleness, low hardness,high mold shrinkage, etc.The toughening PP with elastomers is remarkable, but at the expense of the tensile strength. Inorganic particles can both strengthen and toughen PP materials,however, this effect was limited because the poor compatibility between inorganic particles and the matrix,.To improve the mechanical and thermal properties, the author modified glass fiber, micron talci and nano-SiO₂ with couple agents and grafted by organics. The author used them to modify PP, then investigated their effects on PP composites. We obtained the conclusions as follows:(1) The SiO₂ reacted with the coupling agent 3-(methacry-loyloxyethyl) trimethoxysilane (MEMO), then reacted with acrylic acid by initiated by benzoyl peroxide (BPO). FT-IR, TGA, EDS analysis showed that the acrylic acid was grafted to glass fiber, and the torque rheometer experiment validated the reaction between grafted GF and polymer in blending.(2) Small amount of micron talci improved toughness of PP material slightly. The mechanical properties got a decline when the filling fraction was overstepping. After fillers grafting coupling agent, the mechanical properties improved by about 30% only.(3) The SiO₂ reacted with silane coupling agent 3-glycidoxypropyltrime-thoxysilane (SiO₂-GPS), which contained epoxy, then fabricated hyperbranched poly(ethylene imine) (HPEI) to SiO₂-GPS (SiO₂-GPS-HPEI) with epoxy ring-opening reaction. The structure of modified particles were maded of a core(SiO₂) and a shell(GPS-HPEI). The tensile strength increased by 36.8% at 3wt% usage, and the notched impact strength increased by 96.3% at 2wt% usage. The fracture surface was obviously rougher and more stereoscopic. The obvious yielding and slip cracks existed, they revealed the characteristic of tough fracture. The vicat softening temperature increased by 10.9℃.