AMPS氨化对四元聚丙烯腈原丝结构和性能的影响

利用氨水对2-丙烯酰胺-2-甲基丙磺酸(AMPS)的磺酸基进行氨化改性以制备氨化AMPS,采用丙烯腈、丙烯酸甲酯、衣康酸和氨化AMPS为聚合单体,以偶氮二异丁腈为引发剂,在溶剂二甲基亚砜中经溶液共聚合成了四元聚丙烯腈(PAN)纺丝液,并通过湿法纺丝纺制了碳纤维前驱体四元PAN原丝,分析了AMPS的氨化率对原丝结构和性能的影响。结果表明,AMPS氨化改性后成功将亲水基团NH_4^+引入到四元PAN原丝中;AMPS氨化率为0%～40%时,随着氨化率的增加,纺丝液中共聚物的接触角逐渐减小,原丝的孔隙率先下降后上升,拉伸性能先增大后减小;AMPS氨化率为30%时,原丝的孔隙率最小、拉伸性能最好、截面形貌近似为圆形,其热反应起始温度有所降低、放热峰变宽,最终制得的原丝孔隙率为12.3%,拉伸强度、拉伸弹性模量和断裂伸长率分别为7.5,123.2c N/dtex和15.2%,由此制备的碳纤维拉伸强度、拉伸弹性模量和断裂伸长率达到了4 321MPa,211GPa和2.9%,分别较未氨化时提高了12.4%,6.6%和7.4%。

Effect of AMPS Ammoniation on Structure and Properties of Quaternary Polyacrylonitrile Precursor

Ammoniation modification for sulfonic acid group of 2-acrylamide 2-methyl-propanesulfonic acid(AMPS)was done by using ammonia,the quaternary polyacrylonitrile(PAN)spinning solution was synthesized in the solvent dimethyl sulfoxide through solution copolymerization with acrylonitrile,methyl acrylate,itaconic acid and the ammoniated AMPS as polymerization monomers and azodiisobutyronitrile as initiator,then the quaternary PAN precursor was spun by wet spinning.The effects of ammoniation rate on the structure and properties of the precursor were studied.The results show that,the hydrophilic group NH4+is successfully introduced into the precursor after AMPS ammoniation,when the ammoniation rate of AMPS is 0%–40%,with the increase of the ammoniation rate,the contact angle of the copolymer in the spinning solution decreases gradually,the porosity of the precursor decreases first and then increases,and the changes of tensile properties are opposite.When the AMPS ammoniation rate is 30%,the precursor has the smallest porosity and best tensile properties,the cross-section is approximate circular,the initial temperature of the thermal reaction of the precursor is decreased and exothermic peak is widened,finally,the porosity of the corresponding precursor is 12.3%,the tensile strength,modulus and elongation at break are 7.5,123.2 cN/dtex and 15.2%respectively,the tensile strength,modulus and elongation at break of carbon fiber prepared with the ammoniated precursor reach 4 321 MPa,211 GPa and 2.9%,are increased by 12.4%,6.6%and 7.4%respectively compared with those of un-ammoniated fiber.