Removing By-product Polymaleic Anhydride From CPP-g-MAH With Water Extraction

Due to lower in polarity of them which includes polyethylene, polypropylene, polyvinyl and chlorinated polypropylene, it is difficult to blend them with strongly polar adhesive and coatings. It was one of the most commonly used methods to increase their polarity that grafting maleic anhydride. However, in graft reaction, the graft efficiency were generally lower, a great deal of maleic anhydride change into by-product polymaleic anhydride. There are marked differences in solubility parameter among polymaleic anhydride and polyolefin and the grafts of chlorinated polypropylene, so the grafts of chlorinated polypropylene and polymaleic anhydride are inconsistent. When used as adhesion, it is not too exactitude for the homogeneous of the film coatings' surface. But when used as an assistant of the coatings, it is quite exactitude. It is known that polymaleic anhydride is soluble in water and usually used as anti-incrustator, etc. whereas, chlorinated polypropylene and the grafts of chlorinated polypropylene are insoluble in water, which are poorly polar polymers. Therefore, taking the chlorinated polypropylene grafted maleic anhydride as the example in the thesis; we try the method of using water to separate by-product polymaleic anhydride. These results are very important on the use of the grafts of chlorinated polypropylene as an assistant of the coatings.Above all, the influence of temperature, time, water quantity, with water extraction on the returns-ratio of water scrubbing polymaleic anhydride was reviewed in the thesis. It is found that the influence of temperature is the most important. The higher temperature, the better effect. Then, the technics testing has carried on. The result showed that distilling the toluene out of the constant-boiling mixture is feasible below the constant boiling point of toluene and water. Because the grafts and water full contact in reaction process, maleic anhydride of the grafts will be full hydrolysis. The grafts have been characterized by means of the infrared spectrum, the solubility parameter and the adhesion determination, which shows that the grafts of chlorinated polypropylene with water extraction can be used. There was no obvious difference in the grafts' using effect between with water extraction and with traditional acetone extraction.In this foundation, the dilution ratios of many kinds of solvent are also inspected. It was discovered that the grafts' dilution ratio and the polarity of solvent have related relations. The polarity of solvent can be expressed as the vector sum of the polarity and the hydrogen bond component of Hansen' three dimensional solubility parameter. The stronger of the solvent' polarity, the lower of the dilution ratio of it's of the turbidity titration method. It showed that the grafts of chlorinated polypropylene were still a weak polar polymer. In the end, the solvent choice has been carried on the discussion about the present commonly used turbidity titrimetric method determined solubility parameter .