Study On Blending Modification Of Chloroprene And Fabrication Of Its Composites

Polychloroprene(CR)possesses excellent mechanical properties and good oil resistance,flame resistance and chemical resistance.More application values of CR can be achieved via the blending modification and the fabrication of CR composites.Compared with CR,CR/PVC blends have much lower cost while their compatibility is still a problem.Carboxylated multi-walled carbon nanotubes(MWCNT)can effectively improve the mechanical properties of CR while the dispersion of MWCNT in CR needs to be further improved.The effects of 2,4,6-trimercapto-s-triazine(TCY)and nitrilebutadiene rubber(NBR)on the compatibility of CR/PVC blends were studied.The effect of CMI on the dispersion of MWCNT in CR/MWCNT composites was studied.The structure,properties and hot embossing moldability of polypropylene(PP)/hydrogenated styrene-isoprene-styrene block copolymer(HYBRAR)blends were also investigated.TCY,commonly known as a highly efficient cross-linking agent for rubbers,has a high chemical reactivity with both CR and PVC.CR/PVC blends partially co-crosslinked by TCY were made via mechanical blending,and the mechanism of co-crosslinking reaction between CR and PVC was explored by DSC and FTIR.The effects of blending temperature and TCY content on the crosslinking reaction,mechanical properties,oil resistance and abrasion resistance of CR/PVC blends were studied.Due to the relatively strong interactions between NBR and PVC,NBR can be added into CR/PVC blends as an effective compatibilizer.CR/PVC blends with different NBR contents were prepared via the mechanical blending,and the effect of NBR on the compatibility,morphology,mechanical properties,nonlinear viscoelasticity and thermal stability of CR/PVC blends were studied.With the addition of NBR,glass trantistion temperature and phase size of PVC both decreased significantly,leading to an improved compatibility between CR and PVC.The improved compatibility endowed CR/PVC blends with better mechanical properties.CR/PVC with 10 phr NBR had a higher storage modulus than CR gum vulcanizate,indicating the softening effect of NBR on CR/PVC blends.The relationship between NBR and the improved thermal stability of CR/PVC blends was also analyzed.Non-covalent modification of MWCNT was conducted by a carboxylated ionic liquid(IL),1-carboxyethyl-3-methylimidazolium bis(trifluoromethyl sulfony)imide(CMI).Bucky gel of MWCNT with CMI modified MWCNT(m-MWCNT)was prepared from MWCNT and CMI via an environment friendly solution predispersion.And CR/mMWCNT composites with different MWCNT/CMI ratios were made via mechanical blending.As evidenced by the most obvious Payne effect,the best MWCNT/CMI ratio for CR/m-MWCNT composites was accounted as 1:2.The CMI modification favored to the dispersion of m-MWCNT in CR and enhanced the interactions in CR/MWCNT composites,which promoted the formation of a fine filler network at high m-MWCNT content.Compared to CR/MWCNT composites,CR/m-MWCNT composites possessed better mechanical properties and thermal stability,and higher dielectric constant.PP/HYBRAR blends with different compositions were fabricated via the extrusion blending.The effect of HYBRAR proportion on the crystallization and rheological behavior of PP/HYBRAR blends were studied.Micro pyramid arrays were fabricated on the surface of PP/HYBRAR blend thin-films via the micro hot embossing.The structure of these micro-pyramids became more perfect with the increment of embossing temperature and the increase of HYBRAR proportion.The micro-pyramid array could work as a kind of total reflection prism.With the height of micro pyramid arrays increased,the transmittance of embossed thin-films decreased gradually.These adjustable optical properties indicate that PP/HYBRAR blends have good application prospects in the fabrication of optical films.