Study On Preparation And Properties Of Polymer/Attapulgite Nanocomposites

In the thesis,the attapulgite was treated with small molecule silane coupling agent KH570 and monomer MMA via ultrasonic vibration. Fourier Transform Infrared(FTIR) and X-ray Photoelectron Spectronscopy (XPS) analysis indicated that the coupling agent had been grafted to the surface of the rod-like crystal and the monomer had been polymerization onto the rod-like crystal through free-radical polymerization. Nanocomposites based on polymer and treated attapulgite were prepared by melt blending, structure and properties of them were characterized by X-ray Diffraction(XRD),Different Scanning Calorimetry(DSC)and Transmission Electron Microscopy(TEM).1. TEM analysis indicated that the attapulgite had been dispersed with a single rod-like crystal via ultrasonic treatment, namely showed that the ultrasonic could rupture the agglomeration force among the rod-like crystal, so the uniform dispersed rod-like crystal was achieved.2. Low Density Polyethylene(LDPE)/Alk-AT,LDPE/Alk-AT/PMMA, High Density Polyethylene(HDPE)/Alk-AT/PMMA nanocomposites were prepared by melt blending .XRD,TEM and DSC were used to study the structure and crystallization kinetics of them, and their mechanical properties were tested.It was found that:(l)The value of tensile strength of LDPE/Alk-AT nanocomposite was much higher than the original LDPE at the load of 8wt%,but the value of Izod impact strength showed a descending tendency.Compared to the heterogenous function, the layered and chain structure of the Alk-AT and the increasing content of gel had a dominant limitiond on the chain of PE. The best comprehensive mechanical properties of LDPE/Alk-AT/PMMA nanocomposites were achieved with W(AT)/W(MMA)=5,the grafted attapulgite showed a heterogeneous nucleation function.(2)The best comprehensive LDPE/Alk-AT/PMMA nanocomposites were achieved with W(AT)/W(MMA)=5.The Jeziorny could be applied to describe the nonisothermal crystallization process of HDPE/Alk-AT/PMMA nanocomposite very well. The Ozawa describe the nonisothermal crystallization of HDPE very well,but failured to describe the nonisothermal crystallization of HDPE/Alk-AT/PMMA nanocomposite very well completely.3. Polypropylene(PP)/Alk-AT, PP/Alk-AT/PMMA nanocomposites were prepared by melt blending .XRD,TEM and DSC were used to study the structure and crystallization kinetics of them, and their mechanical properties were tested.It was found that:(l)The value of tensile strength and Izod impact impact strength achiev maximum at the load of 10wt%,2wt% Alk-AT respectively. The Jeziorny and a method of developed by Mo could be applied to describe the nonisothermal crystallization process of PP/Alk-AT nanocomposite very well. The value of Avrami factor n showed the crystallization process of PP/Alk-AT nanocomposites similar with that of originall PP,corresponding to a tridimensional growth with heterogeneous nucleation.(2)The isothermal crystallization kinetics of PP/Alk-AT/PMMA nanocompositesindicated the value of half-time t1/2 of PP/Alk-AT nanocomposite was shorterthan that of original PP, the addition of grafted attapulgite decreased theinterfacial free energy and promote the heterogeous nucleation of PP.4.Polyvinyl chloride(PVC)/Alk-AT/PMMA nanocomposites were prepared by meltblending .XRD,TEM and DSC were used to study the structure and glass transitiontemperature , and their mechanical properties were tested.It was found that the bestcomprehensive PVC/Alk-AT/PMMA nanocomposites were achieved withW(AT)/W(MMA)=5.The grafted attapulgite had a certain influence on the glasstransition of the system.TEM showed the attapulgite was uniform dispersed in thesystem and formed as nanocomposites.