EFFECT OF PLASTICIZER ON THE MOLECULAR WEIGHT AND SOME MECHANICAL PROPERTIES OF POLYVINYL CHLORIDE (PVQ

Polyvinyl Chloride (PVC) is a rigid polymer andfor several of its applications mustbe compounded with plasticizing agents. The plasticizers minimize the dipolar in teractions which exist between the polymers chains, promoting their mobility. In this work, the viscosity average molecular weight (MJ of pure PVC and plasticized PVC solutions in Cyclohexanone at 30°C (±0.5°C) was determined. The effect of amount of plasticizer on the molecular weight was studied. It was observed that limiting viscosity number decreased abruptly from pure PVC to plasticizer PVC solutions and the effect became very less pronounced as the amount of the plasticizer increases. The mechanical properties of pure PVC film cast from solutions was determined and also for PVC/plasticizer systems of varying compositions weight by weight. The films were prepared by casting a 2% solution of pure PVC and plasticized PVC on a Petridish and at 3(fC for 48hours, yielding films of average thickness 0.087mm. Generally, the ultimate tensile strength and modulus of elasticity decrease as the amount of plasticizer increases while the elongation at break increases with increasing amount of plasticizer. Plasticization reduced the ultimate tensile strength and modulus of elasticity but increased the elongation at the break of thefilm remarkably.