Polypropylene reinforced with glass fiber has  higher dimensional stability than pure polymers and a piece which is made of it, is wraping less. Polypropylene reinforced with glass fiber improves in term of mechanical strenghth anf hardness and with adding 40% glass fiber , thermal expansion cofficent is reduced by half. with adding 30% glass fiber,Tensile strenght is increased 180%.However, if right glass fibers aren't used, tensle strenght  is increased only 50%

 

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