Research On The Graft And The Emulsification Of Polypropylene Wax

As the physical properties of glass fiber and polypropylene are quite different,it makes polypropylene difficult to infiltrate glass fiber and glass fibers difficult to disperse into polypropylene base homogeneously,which makes glass fiber reinforced effect reduced greatly.In order to reinforce the property of the fibrous composite,the modified polypropylene wax emulsion is prepared by the grafting modification method.The research of this aspect,which is still few in our country,was mainly done in the United States,Japan.etc.In this paper,the modified polypropylene wax emulsion was studied.In this paper,preparing a stable polypropylene wax emulsion is as a focal point to be studied.The content of this paper is divided into two parts.One is the grafting modification of polypropylene wax,the other is the synthesis of modified polypropylene wax emulsion.The concrete work includes the following aspects.In the first part the polypropylene wax is grafted according to the solution grafting method.That whether the methacrylic acid and the styrene have been successfully grafted onto the molecular chain of the polypropylene wax is verified by the infrared spectrum.Later the grafting yields are determined by chemical titration.The priority-rate of the grafting yield which are the monomer ratio,the ratio of the monomer and the polypropylene wax and the temperature is investigated through the designed orthogonal experiment.At the same time, the best technological condition of high grafting yield is obtained,that the temperature is 90℃,the monomer mole ratio of the methacrylic acid and the styrene is 2:1,and the mass ratio of the monomer and the polypropylene wax is 0.7:1.The quantitative characterization of the graft is studied by using the infrared spectrum method and the chemistry titrimetric method.The linear relationship between the grafting yield by chemical titration method and the relative grafting yield which is the ratio of the graft's IR characteristic peak is associated by the least square method.The formula which can be used on the semi-quantitative analysis of the polypropylene wax's grafting yield is raised.The formula can be used to roughly indicate the extent of the grafting reaction.The second part is the preparation of the modified polypropylene wax emulsion on the optimum condition.The modified polypropylene wax is prepared by the solution grafting process,and then the modified polypropylene wax water-based emulsion is prepared by plusing the aqueous solution of amine in the mixture without separation.The products are characterized by FTIR and the optical microscopy.The properties of different grafting yield's emulsions are studied.The results show that if the rafting yield is too low, the emulsion prepared is unstable and layered,and it also show that if the grafting yield is too high,the viscosity of the emulsion prepared as well as the emulsion's average particle size increases and the emulsion's stability is reduced.Finally,the conclusion that the grafting yield is not a determinant on preparing a good emulsion is obtained.In order to obtain an excellent emulsion,various factors such as the purpose of the emulsion,viscosity,particle size,solid content and stability,should be comprehensively considered.The amine salt of the graft copolymer,which is a self-emulsification emulsifier,is proved by studying the grafting copolymer and the modified emulsion.Comparation of the ultrasound emulsion with non-ultrasound emulsion shows that ultrasound can make the emulsion's particle size small and make the static stability and water-dispersibility of the emulsion improved.Therefore it is very necessary to ultrasound for the purpose of getting an excellent modified polypropylene wax emulsion.By the comparation and analysising of each emulsion,the best technological condition of an excellent modified polypropylene wax emulsion is obtained.The molecular weight of polypropylene wax is between 9000-11000,the temperature and the neutralization degree are 90℃and 120%,the monomer mole ratio of the methacrylic acid and the styrene is 2:1,and the mass ratio of the monomer and the polypropylene wax is 0.7:1.