Influences Of Impurities On Solubility Parameter Of Chlorinated Polypropylene

Solubility parameter has caught a wide attention in polymer industry ,since it is a powerful weapon in the study of polymer dissolved ,but the study showed that it only could be used in pure substances. Raw materials or products in industrial production or experimental study always are not pure, which contain more or less impurities or additives, all of these limit the use of solubility parameter,and we should purify the products in the course of study and research, or simply to ignore the impact of the impurities. There has been not relevant reports whether or not the existence of impurities in the polymer put influence on its solubility parameter. In this paper,we choose chlorinated polypropylene a adhesion promotion in coatings an example of studing to show the impact of impurities to solubility parameters of polymer in order to using solubility parameters in these systems.TLC is used to verify the existence of impurities in CPP-4 firstly. The best experiment condition was selected to purify CPP. Then the chlorine content of four kinds of CPP both before and after the purification was analyzed and the results were discussed. The impurities in CPP-2 which contains about 30 percent of chlorine used in ink are by-products with high chloride content. As for the impurities in CPP-4 which contains about 25 percent of chlorine used in coatings,it is added to improve its performance by adding artificial, and its chlorine content is lower than the original pure samples'.The solution of four kinds of CPP both before and after the purification was tested in various solvents. The results show that the dissolution performance of samples before and after the purification has not changed in the 38 kinds of solvents we choosed. The three-dimensional solubility parameter of CPP-2 and CPP-4 was obtained by Hansen method. The accuracy of three-dimensional solubility parameter determined by Hansen method was discussed.Turbidimetric titration is the most classic way to test the polymer's solubility paramete. A unified method to determine the cloud point was indentified firstly in this paper which could improve the accuracy of the results,because the judgement of the cloud point is the kay reason in experimental error. The impacts of solvents and non-solvents to solubility parameters determined by turbidimetric titration were studied. The solubility parameters of CPP was experimented ,the result showes that the solubility parameter is on the rise while the chlorine content increasing.The solubility parameter of impurities in CPP-4 was determined by inherent viscosity .Its solubility parameter is higher than the solubility parameter of CPP-4 after purification determined by Hansen method and turbidimetric titration ,indicated that the polar of impurities is higher than purity CPP-4.