Study On HEMA/DVB Functional Modification Of IPB-1 And The Crystallization Properties Of IPB-1 Composites

Isotactic polybutene-1(iPB-1)was functionallized using dicumyl peroxide(DCP)as initiator,hydroxyethyl methylacrylate(HEMA)as grafting monomer,and divinylbenzene(DVB)as comonomer to prepare iPB-g-HEMA in a torque rheometer.The effects of reaction temperature,reaction time,DCP content,HEMA content and DVB content on the grafting degree,grafting efficiency,melt flow rate(MFR)and tensile properties of iPB-g-HEMA were investigated,respectively.The results showed that HEMA and DVB grafted to the iPB-1 molecular chain successfully,and different factors made different grafted samples.DCP and DVB could decrease the tensile properties of the grafted samples,while the increased content of HEMA could improve tensile performance.When the reaction temperature was 175 ?,the content of DCP and HEMA were 0.4 phr and 6 phr respectively,the mass ratio of DVB and HEMA was 1:1,the grafting degree of HEMA was 2.23%.HEMA grafted chain increased the polarity and hydrophilicity of iPB-1.The contact angle changed from 92.5°to 65°.DSC test results showed that the crystallization temperature(Tmc)of iPB-g-HEMA was higher than that of iPB-1 and the half peak width was narrowed.What's more,with the increase of grafting degree,the melting temperature(Tm)and Tmc of iPB-g-HEMA increased and the half peak width was gradually narrowed,which indicated that the grafted chain could significantly accelerate the crystallization rate of iPB-1.The study of non-isothermal crystallization showed that under the same cooling rate,with grafting degree of iPB-g-HEMA increasing,initial crystallization temperature(Ti),peak crystallization temperature(Tp)and end of crystallization temperature(Te)higher than that of iPB-1,shifted to higher temperature and half crystallization time(t1/2)that were less than that of iPB-1 decreased gradually.The results indicated that the increased grafting degree made crystallization rate of iPB-1 faster.With the increase of cooling rate,Ti,Tp and Te of iPB-1 and grafted samples shifted to lower temperature and t1/2 shortened,which resulted in the poor uniformity and perfection of crystal and faster crystallization rate.Study on non-isothermal crystallization kinetics of iPB-1 and grafted samples,the results showed a good linear relationship calculated by the methods of Ozawa and Mo.With the increase of grafting degree,the value of F(T)decreased which meaned the grafted chain could accelerate the crystallization rate.The activation energy of non-isothermal crystallization was calculated by Kissinger equation.The activation energy of iPB-1 was-72.89 KJ/mol that was higher than iPB-g-HEMA.What's more,the increased grafting degree led to lower activation energy.The crystalline morphology of iPB-1 and grafted samples were observed by polarizing microscope.Compared to iPB-1,the number of nuclei of grafted samples increased obviously and the spherulite size decreased.Moreover,with grafting degree increasing,the number of nuclei increased and the grain refined.Thermal stability of iPB-1 and grafted samples were studied by thermogravimetric analysis.Compared to iPB-1,initial decomposition temperature of grafted samples decreased,which showed thermal stability of iPB-1 decreased.But temperature of 50% loss weight content and biggest loss rate were higher than that of iPB-1.The increased grafting degree resulted in increased the three kinds of temperature.The thermal degradation activation energy calculated by the Coats-Redfern and Newkirk processes was consistent with the thermogravimetric data.Mechanical properties test showed that the tensile properties of iPB-1 decreased and the flexural properties improved.Diatomite/iPB-1 composites,POM/iPB-1 composites and PP/iPB-1 composites were prepared by melt blending method and characterized by DSC and polarizing microscope.The results showed that POM and iPB-1 were incompatible so that they crystallized respectively when cooling from the melt.With the increase of POM mass fraction,the morphology of spherulite size changed little.Diatomite and PP had great influence on the crystallization morphology of i PB-1.With the increase of the mass fraction of diatomite,the number of nuclei and the spherulite size significantly changed.DSC data showed that compared with iPB-1,diatomite,POM and PP could improve the crystallization temperature and the crystallization rate of the composites.