Research On Nanometer Inorganic Modification Of EVA, LLDPE And Their Blends

With the development of electronic information and family electric industry,the functional requirement for the macromolecule memory material is rising,for example,Pyrocondensation tubules' diameter can be made as small as0.1mm to 1mm if the breakdown voltage resistance of the material is above10KV.Single EVA or LLDPE as matrix material needs insistent improvement fortheir shortages of function and performance. Generally, Al(OH)₃, TiO₂, ZnOand CaCO₃ are added in macromolecule memory material matrix as commoninorganic fillings. Because the size of their particle is relatively too big, theyare not compatible enough with the polymer matrix material. So when they areblend with polymer, small holes are formed, and that greatly reducebreakdown voltage resistance electricity insulation and flexibility of the material.How to resolve this problem is inevitably become a bottleneck of the research ofmacromolecule material matrix.Recently, polymer/inorganic nano-particle composite materials of which thematrix are macromolecule materials become a hotspot in the researches oftheory and application of macromolecule material. They possess importantsignificance in the development of the high performance and functionalcomposite material. They have wiped off parts of deficiency of single materialand traditional composite material, and exerted cooperation effect of allcomponents. They have all the characteristic of mineral, organism andnano-material, and possess some excellent performance that single componentmaterial does not have. Therefore, the author consider it a good way to resolvethe problem by using nano-particle in the place of traditional filling to preparenew matrix material. Molten blend method,as it is easy to operate, apply, andindustrialize,is become a very effective method to prepare polymer/inorganicnano-particle composite material, and that, it has formed and become awell-rounded way in the producing the molecule memory matrix material. So weuse molten blend method in our experiments.In this text, on the purpose to design formula for the chemical compound,we used banbury mixer molten blend method, and did a great many ofexperiments. We used EVA, LLDPE and their blend composite material asmatrix, and prepared a series of EVA/inorganic nano-composite material,LLDPE/inorganic nano-composite material , and EVA/LLDPE/inorganicnono-composite material by filling different proportion, single or multinano-particle (contain nanometer Al2O3, SiO2, TiO2, ZnO and CaCO3 ). Wesystematically studied the relation between their performance and structures,and made a deep exploration and analysis in high performance, application,and theory research, then a great deal of valuable data was obtained. Whichbecome the theory base of the exploration and application of the highperformance polymer composite material. We also had made a newpolymer/inorganic nano-composite material which would possibly be the masterbatch of the pyrocondensation tube material. The main study of the text can besummarized to several aspects as follow:1.We used direct dispersion method (filling with the primary nano-particle),one-step method (coupler was added as a component, filling with the primarynano-particle) and two-step method (filling with the nano-particle which hadbeen activated) to prepare EVA/nano-Al2O3,EVA/nano-TiO2, and EVA/nano-SiO2 composite materials. The dispersibility of these nano-particle and theappearance of fracture was characterized by FESEM, FTIR and SEM, and themechanical and rheological properties of the composite materials was also study.The result indicate that the nano-particle will be easier dispersed in the matrix ifVinyltriethoxysilane(Silane coupling agent)is added as a component and directlyblended it with matrix EVA and the dispersion phase. Compared with other twomethods, one-step method is the best in improving mechanical property, andis easy to manipulation. It has a certain application foreground, and worth tomake a further exploration. Though nano-Al2O3, nano-TiO2 and nano-SiO2 aredistributed in EVA matrix material in different tight degrees and states in theone-step method system, their dispersibility is relatively equal, and theirparticle diameter is less than 100nm,they are basically in nanometer dispersionstate. There exist chemical bonds between nano-particle and EVA,the degree ofyield and toughness of the matrix material is increased. We studied thecomposite material of EVA/nano-TiO2, when the particle filling quantity is5%, the tensile strength is increased by 22.6%;when the particle fillingquantity is 1%, the elongation at break is increased by 10.1%. To compositematerial of EVA/nano-Al2O3, the tensile strength and elongation at break ofEVA/Al2O3 nano-composite material were increased by 25.4% and 12.1%,respectively, in which they are firstly increased and subsequently reduced. Tocomposite material of EVA/nano-SiO2, when the particle filling quantity is1%,the tensile strength and elongation at break of EVA/SiO2 nano-compositematerial were increased by 16.1 and 11.7%, respectively, and in which theyfirstly increased and subsequently reduced. Furthermore,we discovered anabnormal phenomenon that in a certain dispersion phase filling quantity, theapparent viscosity of nano-composite materials mentioned above were lowerthan pure EVA, and its melt point was change very little. So the fluidity iseffectively improved.2. After selecting the surface modification method of inorganic nano-particleand the type and content of surfactant, we used direct dispersion method andtwo-step method to prepare LLDPE/nano-Al2O3 composite material ,LLDPE/nano-TiO2 composite material,LLDPE/nano-ZnO composite materialand LLDPE/nano-ZT composite material (the compound of nano-ZnO and nanoTiO2). We also systematically studied relationship between the mechanical andrheological properties of composite material and the prepared method, theselection of surfactant,the type of nano-particles and its content, andcharacterized the dispersion,structure and rupture surface appearance of all typeof nano particle that dispersed in the matrix material. The results indicated thatusing 2% weigh of nano particle filling quantity NDZ-101 titanate couplingagent could effectively modify all kinds of the nano-particle mentioned in thistext. Two-step method is better than direct dispersion method in improving themechanical property. When the particle filling quantity is 3%, they all achievetheir maximum of tensile strength and impact strength. Using these methods canimprove both yield stress and toughness of the matrix. The apparent viscosity ofmelt prepared by two-step method is lower than that prepared by directdispersion method, when the particle content is lower than a certain value andthe shear velocity is slower, their apparent viscosity is even lower than pureLLDPE melt, this indicate that the melt are improved in their fluidity.Nevertheless, two-step method can make it possible for " nano-Al2O3,nano-TiO2,nano-ZnO and nano-ZT" to form firmly bonded structure,improveinterface link strength and the dispersibility of nano particle in the matrix, andachieve nano-grade dispersion.3.We prepared LLDPE/EVA/nano-Al2O3 composite material ,LLDPE/EVA/nano-TiO2 composite material,LLDPE/EVA/nano-ZnO compositematerial, and LLDPE/EVA/nano-ZT composite material by direct dispersionmethod and two-step method, and we characterized the dispersibility,structure and surface appearance of rapture of all type of nano-particle byFESEM, FTIR and SEM, and studied their mechanical and rheologicalproperties. The results indicated that both two method could improve themechanical property of the composite system,but the two-step method wasbetter. When the filling quantity is 2%³%, the tensile strength of thesematerial is best,and their matrix display toughness broken. Compared with thedirect dispersion method, two-step method can reduce the apparent viscosity ofthe composite material melt, and at the relatively lower shear velocity, theapparent viscosity were even lower than LLDPE/EVA composite, their meltindex were increased relatively,which proved that their fluidity are improved.Nevertheless,two-step method can make it possible for " nano-Al2O3,nano-TiO2,nano-ZnO and nano-ZT" to form firmly bonded structure, improveinterface link strength and the dispersibility of nano-particle in the matrixmaterial, and achieve nano-grade dispersion.4.We filled LLDPE/EVA/nano-CaCO3 composite system with nano-ZTparticle and characterized the dispersibility, structure and surface appearanceof rapture of all type of nano-particle by FESEM,FTIR and SEM, and studiedtheir mechanical and rheological properties. The result indicated that the tensilestrength decreased 30% when 20% weight of nano-CaCO3 was filled inLLDPE/EVA composite material. When filling composite material with nano-ZTparticle, the two-step method is superior to the direct dispersion method inimproving their tensile strength. Compared with LLDPE/EVA/CaCO3 compositesystem,when the filling quantity of nano-ZT was 2%,the tensile strength of thecomposite material that prepared by two-step method was increasing by 23%,and this remedy the reduced mechanical property caused by filling nano CaCO3.Moreover, filling LLDPE/EVA composite material with 20% CaCO3 canincrease the rigidity of the composite system. The composite material filled withnano ZT that dispersed by two-step method was lower than that dispersed bydirect method in the rigidity, but they have much better stability. Adding 20%CaCO3 into LLDPE/EVA composite material could decrease its toughness, andadding nano ZT particle by two-step method could increase the yield property ofthe matrix material. When the matrix material was ruptured, tiny fibers andfiber bundles which dispersed and connected themselves was formed. Adding20% nano-CaCO3 to LLDPE/EVA composite material could increase apparentviscosity of the melt, and the appearance viscosity of composite prepared bytwo-step method was lower than that prepared by direct dispersion method.When the content of nano-ZT was lower than 3%,and at a lower shear velocity,their apparent viscosity were even lower than LLDPE/EVA/nano-CaCO3composite material,which proved that the fluidity was effectively improved.Nevertheless,there formed firm bonded structure between LLDPE/EVA matrixmaterial and activated nano-CaCO3 , nano-CaCO3 and organic modifiednano-ZT. The dispersion phase was in a complex state in the direct dispersioncomposite system. In composite system prepared by two-step method, thedispersion phase distributed in primary particle which equally concentrated in anarea that smaller than 100nm and 100nm round. Moreover,they formed aninteresting chain array structure that worth to further discuss.In conclusion,our study in the text was not only the simple preparation ofcomposite material by filling and blending different kinds of nano-particle withEVA,LLDPE,and their blended composite materials,but elaborately combinedtraditional design formula for the chemical compound and nano-compositetechnique of new polymer/inorganic particle composite material. We deeplyresearched relatively theory and provided experimental datum and technical ideafor researchers who are engaged in the similar research. At last,we have made asuperiority new polymer/inorganic nano-composite material,which extend thetype and application field of composite material .