为改善聚对苯二甲酰对苯二胺(PPTA)的加工性能,通过调控PPTA聚合时的单体摩尔比,制得具有酰氯和胺基封端的PPTA预聚物溶液,并将其作为新型反应单体在N-甲基吡咯烷酮(NMP)/CaCl2复合溶剂中进行二次聚合,获得了可直接加工的高分子量PPTA(HMW-PPTA)溶液。探究了聚合条件对PPTA预聚物及HMW-PPTA比浓对数黏度(ηinh)及状态的影响,并分析了两者的化学结构及溶液性能。结果表明:单体摩尔比能显著调控PPTA预聚物的ηinh和状态,当单体摩尔比为1.06∶1时可获得兼具高反应活性和加工流动性的PPTA预聚物溶液;在二次聚合过程中,当预聚物反应摩尔比为1∶1、二次聚合浓度为3%时,可制得ηinh高达4.1dL/g且呈现均相透明溶液状态的HMW-PPTA溶液。结构分析结果显示,PPTA预聚物与HMW-PPTA具有一致的化学结构,但活性端基数目的减少以及分子量的增加改善了HMW-PPTA的热稳定性,并且HMW-PPTA溶液相较于PPTA预聚物具有更高的表观黏度。
To improve the processability of poly(p-phenylene terephthalamide) (PPTA),PPTA prepolymer solutions terminated with acyl chloride and amine groups were prepared by controlling the monomer molar ratio during PPTA polymerization.These prepolymers were then used as novel reactive monomers for secondary polymerization in N-methylpyrrolidone (NMP)/CaCl2 composite solvent,yielding directly processable high-molecular-weight PPTA (HMW-PPTA) solutions.The effects of polymerization conditions on the inherent viscosity (ηinh) and state of both PPTA prepolymers and HMW-PPTA were investigated,and their chemical structures along with solution properties were analyzed.The results indicated that the monomer molar ratio could significantly regulate the ηinh and state of the PPTA prepolymers.A monomer molar ratio of 1.06∶1 yielded a PPTA prepolymer solution with both high reactivity and processing fluidity.During the secondary polymerization process,an HMW-PPTA solution with a ηinh as high as 4.1dL/g and a homogeneous,transparent solution state was obtained when the prepolymers reaction molar ratio was 1∶1 and the secondary polymerization concentration was 3 wt%.Structural analysis revealed that the PPTA prepolymers and HMW-PPTA shared identical chemical structures.However,the reduced number of active end groups and increased molecular weight improved the thermal stability of HMW-PPTA.Furthermore,the HMW-PPTA solution exhibited higher apparent viscosity compared to the PPTA prepolymer solutions.
[1] 沈逍安,王晓映,夏光美,等.芳纶的发展现状及其表面改性研究进展[J].合成纤维,2021,50(1):20-25.
[2] 李杉杉,尚诗杰,王娜娜,等.对位芳纶纤维界面改性技术研究进展[J].复合材料学报,2025,42(3):1192-1206.
[3] Wang Y F,Tuo X L,Ye G.Self-healing heterocyclic aramid nanofibers as dynamic interfacial cement for fabricating hybrid aramid paper[J].Chemical Engineering Journal,2025,511:161662.
[4] Wang Y F,Ding X Y,Wang H R,et al.Highly efficient and durable aramid nanofibers/carbon nanotubes-coated electrothermal paper[J].ACS Applied Polymer Materials,2024,6(13):7612-7620.
[5] Dewilde S,Winters J,Dehaen W,et al.Polymerization of PPTA in ionic liquid/cosolvent mixtures[J].Macromolecules,2017,50(8):3089-3100.
[6] 庹新林,李京龙,闫鸿琛,等.聚对苯二甲酰对苯二胺纤维的研究进展[J].高分子通报,2015(9):171-186.
[7] Liu L J,Wang L D,Li K W,et al.Cool spinning strategy for high-performance thick aramid fibers[J].Advanced Fiber Materials,2025,7:2048-2060.
[8] Yang C,Wu H,Dai Y,et al.Constructing mainstay-body structure in heterocyclic aramid fiber to simultaneously improve tensile strength and toughness[J].Composites Part B:Engineering,2020,202:108411.
[9] Li Y H,Shi Q L,Wang Y D,et al.Scalable wet-spinning of aramid nanofibers-assisted graphite films for broadband electromagnetic interference shielding with Joule heating[J].Chemical Engineering Journal,2025,522:167629.
[10] Chu G Y,Nie Z G,Peng Y M,et al.Spin-coating ANF based multilayer symmetric composite films for enhanced electromagnetic interference shielding and thermal management[J].Journal of Colloid and Interface Science,2025,679:521-530.
[11] Ma Q,Yao J R,Shen C,et al.Multifunctional ANF/CNT/FCIP aerogels with superior sound and electromagnetic wave absorption and mechanical properties[J].Chemical Engineering Journal,2024,500:156897.
[12] Han G J,Zhou B,Li Z Y,et al.Ultrafine aramid nanofibers prepared by high-efficiency wet ball-milling-assisted deprotonation for high-performance nanopaper[J].Materials Horizons,2023,10(8):3051-3060.
[13] Yang G L,Wang L F,Ma Y X,et al.Light-induced ion transport and energy harvesting through aramid nanofiber-functionalized indium selenide nanochannels[J].ACS Sustainable Chemistry & Engineering,2025,13(38):15839-15846.
[14] 曹煜彤.对位芳纶产业化关键新技术及其机理的研究[D].上海:东华大学,2010.
[15] Li N,Song S B,Yu J R,et al.Novel fabrication of hydrophobic poly(p-phenylene terephthalamide) paper with superior tear strength and high dielectric breakdown strength[J].Composites Science and Technology,2023,243:110266.
[16] 张兴珂.高加工性能聚对苯二甲酰对苯二胺溶液的制备与应用研究[D].上海:东华大学,2021.
[17] Sun H J,Meng X X,Luo C F,et al.Quantifying crystallinity in poly(p-phenylene terephthalamide) by Raman spectroscopy[J].Macromolecules,2024,57(15):7390-7397.
[18] Lei J,Gui Z X,Xiong W T,et al.Boosting thermal stability and crystallization of closed-loop-recyclable biodegradable poly(p-dioxanone) by end-group regulation[J].Science China Chemistry,2023,67(2):642-651.
[19] An B Y,Xie Z M,Jiang B A,et al.Determination of the free volume of thermosetting polymers[J].Polymer,2025,323:128187.
[20] Wang H R,Zhang L,Peh K W E,et al.Effect of phase separation and crystallization on enthalpy relaxation in thermoplastic polyurethane[J].Macromolecules,2022,55(19):8566-8576.
基金资助
新材料重大专项项目资助(2024ZD0602400);上海市青年科技英才扬帆计划资助(24YF2700600)
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