Preparation Of Water-based PSA With High Performance And Study On Modification Of Wollastonite

This thesis includes two parts, the first part is about the preparation of water-based PSA with high performance and the second part is about the modification of wollastonite.Compared to other PSAs, polyacrylate emulsion PSA has great advantages. So it is necessary to study on the influencing factors which may affect its performance. In this paper, we use BA and2-EHA as the soft monomers, MMA and St as the hard monomers, AA and HEA as the functional monomers, OP-10and SDS as the emulsifiers, K2S2O8as the initiator to prepare high-performance PSA by seeding emulsion polymerization. During the preparation, the reaction temperature is84℃, the temperature in the insulation stage is86℃, the reaction time is3hours, the holding time is one hour, and the stirring speed is150r/min.The desired targets of the performance of PSA are as follows:the180°peel strength exceeds10N/25mm, the adhesion should be above24hours, the viscosity and initial viscosity are moderate. We found it that we could achieve them when2-EHA is50%in the soft monomer, the ratio of MMA and St is1/1.3, the ratio of soft monomers and hard monomers is7, the ratio of OP-10and SDS is5, the content of the emulsifier is2%, the content of the initiator is0.7%and the content of the seeding emulsion is10%. It is also found that the viscosity increase with the reduce of the particle size of the emulsion. In this paper, we also studied the influence of the closed cross-linking agent (XC-327) and the non closed cross-linking agent(XC-113) on the properties of PSA. And the results show that the best content of XC-327is2%, and the best content of XC-113is1.5%.Wollastonite which has widespread use must to be modified as its poor compatibility with polymer materials. In this paper, we firstly choose raw1among three kinds of wollastonite as the basis material via TGA, SEM and the analysis of activation index. And then, according to our objective-the oil absorption value is around0.75and seldom are sinking in the water, we come to a conclusion that the silane coupling agent and stearic acid are used as the modifiers, and three modified samples are better modified than others, and modified sample1is the best. At last, we ensure the successful modification of the three samples through the analysis of TGA, IR and SEM.We also discuss the influence of the PP’s mechanical properties including tensile strength, elongation at break and impact strength, when PP is mixed with three types of wollastonite and three modified samples. The results show that three modified samples can significantly improve PP’s tensile strength and impact strength, and sample1is the best among them. And it is also showed that the best added content is15%. At last, we have researched the change of PP’s crystallization and melting behavior when add three modified wollastonite into PP. The outcome indicates that all of the three modified wollastonite decrease the crystallization rate of PP and improve the crystallinity of PP. And among them, sample1changes more, which further proves the viewpoint that sample1is the most successful modified sample.