为探究对位芳纶在高温条件下的降解性能与降解机理,采用高温对其进行焙烘,借助热重分析仪、红外光谱仪、X射线衍射仪、乌氏黏度计、万能材料试验机等测试手段分析对位芳纶纤维热降解温度、分子结构与力学性能的变化情况。结果表明:350℃以下时,对位芳纶的分子结构、热学性能与力学性能保持相对稳定,超过350℃后,纤维分子结构随温度的增加逐渐出现裂解与交联,纤维的热学性能与力学性能则呈现下降趋势;超过450℃时,对位芳纶纤维的结晶度与取向度有一定程度下降,特性黏度与各方向晶面表观晶粒尺寸自温度上升有不同程度的增加,热降解符合二级反应动力学规律。
The degradation properties and mechanism of para aramid under the condition of high temperature were characterization of thermal degradation temperature,molecular structure and mechanical properties with the help of thermogravimetric analyzer,infrared spectrometer,X-ray diffractometer,ubbelohde viscometer,universal material testing machine and so on.The results showed that the molecular structure,thermal and mechanical properties of the para-aramid fiber remained relatively stable when the temperature was below 350℃.When the temperature was above 350℃,the molecular structure of the fiber cracked and crosslinked gradually,while the thermal and mechanical properties of the fiber decreased with the increasing of temperature.When the temperature was above 450℃,the crystallinity and orientation of the fiber decrease to a certain extent,and the intrinsic viscosity and apparent grain size of crystal surfaces increased to varying degrees with the increasing of temperature.The thermal degradation accorded with the second-order reaction kinetics.
[1] Rebouilat S,Peng J C,Donnet J B.Surface structure of Kevlar fiber studied by atomic microscopy and inverse gas chromatography[J].Polymer,2000,41(12):4761-4764.
[2] Morgan R J,Pruneda C O,Steele W J.The relationship between the physical structure and microscopic deformation and failure processes of poly(p-phenylene terephthalamide) fibers[J].Journal of Polymer Science:Polymer Physics Edition,1983,21(9):1757-1783.
[3] Kunugi T,Watanabe H,Hashimoto M.Dynamic mechanical properties of poly(p-phenylene terephthalamide) fiber[J].Journal of Applied Polymer Science,1979,24(4):1039-1051.
[4] Li J,Tian W,Yan H.Preparation and performance of aramid nanofiber membrane for separator of lithium ion battery[J].Journal of Applied Polymer Science,2016,133(30):43623.
[5] Cao K,Siepermann C P,Yang M.Reactive aramid nanostructures as high-performance polymeric building blocks for advanced composites[J].Advanced Functional Materials,2013,23(16):2072-2080.
[6] Park B,Lee W,Lee E.Highly tunable interfacial adhesion of glass fiber by hybrid multilayers of graphene oxide and aramid nanofiber[J].Acs Applied Materials &Interfaces,2015,7(5):3329-3334.
[7] Rao Y,Waddon A J,Farris R J.Structure property relation in poly(p-phenylene terephthalamide) (PPTA) fibers[J].Polymer,2001,42(13):5937-5946.
[8] Ahtee M,Hattula T,Mangs J,et al.An X-ray diffraction method for determination of crystallinity of wood pulp[J].Paperi Ja Puu,1988,8:475-480.
[9] Bohn A,Fink H P,Ganster J,et al.X-ray texture investigations of bacterial cellulose[J].Macromolecular Chemistry and Physics,2000,201:1913-1921.
[10] Downing J W,Jr Newell J A.Characterization of structural changes in thermally enhanced Kevlar-29 fiber[J].Journal of Applied Polymer Science,2004,91:417-424.
[11] Alberto C M,Amelia M A,Juan M D,et,al.Porosity development in chars from thermal decomposition of poly (p-phenylene terephthalamide)[J].Polymer Degradation and Stability,2009,94(10):1890.
