聚偏氟乙烯挤出加工及改性研究

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1、摘要聚偏氟乙烯挤出加工及改性研究聚偏氟乙烯(Poly(vinylidenefluoride)，简称PVDF)是氟树脂中机械强度最优越的材料。PVDF在一定温度和压力下仍能保持良好的强度，韧性好，硬度大，耐磨性好，具有突出的抗紫外线和耐气候老化的性能和化学稳定性。同时PVDF热稳定性良好，便于加工。但因为其本身熔体强度大，不易进行吹膜成形，而且PVDF的粘接能力差，也限制了它作为薄膜的使用。本实验将PVDF粉末与聚甲基丙烯酸甲酯(PMMA)颗粒物理共混后采用熔融挤出的方法制备成复合薄膜。通过差示扫描量热(DSC)，X射线衍射(XIm)，原子力显微镜(AFM)和X射线光电子能谱仪(

2、XPS)等方法研究了随着PMMA含量变化共混薄膜表面一定范围内的形态和组成。研究发现：PVDF与PMMA具有良好的相容性，两者间的相互作用阻碍了PVDF在共混体系中的结晶，PMMA的加入降低了PVDF的结晶能力和熔融温度。通过红外吸收光谱证明了PVDF与PMMA的基团之间类氢键力的存在。PVDF在共混体系中可以发生明显的表面富集现象，表面自由能低的PVDF在表面相的含量大于体相。另外，还研究了钛白粉(Ti02)的添加对共混体系性能的影响。结果表明，钛白粉的添加会增加共混体系的粘度，导致加工时体系温度骤然升高，极易造成PVDF的分解。关键词：聚偏氟乙烯，聚甲基丙烯酸甲酯，挤出加工

3、，薄膜，改性摘要STUDYONEXTRUSIONPRoCESSINGANDMODIFICATIONOFPOLY(VINYLIDENEFLUORIDE)ABSTRACTPoly(vinylidenefluoride)(PVDF)isapolymerwiththehighestmechanicalstrengthinallkindsoffluoroplastics．PVDFmaintainsexcellentstrengthunderhightemperatureandpressure．PVDFhasgoodpropertyoftoughness，hardness，wear-res

4、istance，UV-resistanceandanti—aging，excellentchemicalstability．Furthermore．PVDFhasgoodheatstabilitywhichiSavailableinmoldingprocessing．Ontheotherhand，PVDFpossessessomedisadvantageslikethehighstrengthundermeltingstatewhichisnoteasilyprocessedandbubbling．PVDFhaspooradhesionwhichlimitsitsapplica

5、tionasfilms．Inthiswork，filmsofbinarypolymerblendcomprisingofhydrophobicpoly(vinylidenefluoride)(PVDF)andpoly(methylmethacrylate)(PMMA)havebeenpreparedbymelting．extrusion．ThedependenceofsurfacestructureandcompositionofthefilmsonthePMMAcontentintheblendwasinvestigatedbyusingdifferentialscannin

6、gcalorimeter(DSC)，XRD，atomicforcemicroscope(AFM)，andX-rayphotoelectronspectroscopy．IthasbeenfoundthattheinteractionbetweenthetwopolymerspreventsPVDFfromcrystallizationintheblend．PMMApreventsPVDFfromcrystallizationandreducesthemeltingtemperature．TheFT-IRspectraoftheblendswithdifferentPMMAcont

7、entclearlyshowsthattheoccurrenceofthehydrogenbondingbetweenthefunctionalgroupofthetwopolymers．ThesurfaceenrichmentphenomenonOCCURSintheblendandPVDFwithlowerfreeenergyintheblendtakeupmoresurfacepositions．TheinfluenceoftheadditionofTi02tothesystemwas