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摘要
以单一水溶性无机铵盐过硫酸铵(APS)为引发剂,在水/二甲基甲酰胺(H2O/DMF)混合溶剂中,采用沉淀聚合工艺合成了高分子量的丙烯腈/丙烯酰胺(AN/AM)共聚物(即PAN聚合物)。主要探讨了高H2O含量下的混合溶剂配比和单体配比对聚合反应转化率和产物黏均分子量的影响,并采用元素分析仪(EA)、傅里叶变换红外光谱仪(FT-IR)、广角X射线衍射仪(WAXD)和差示扫描量热仪(DSC)对PAN聚合物的结构和性能进行了表征。结果表明:随混合溶剂中H2O含量增加,PAN聚合物黏均分子量逐渐降低,聚合反应转化率先升高后降低。随喂料中AM共聚单体的含量增加,PAN聚合物黏均分子量和聚合反应转化率呈先升高后降低的趋势。同时,PAN聚合物中O元素含量逐渐增加,表明共聚物中AM单元含量增大,且FT-IR谱图中氰基(C≡N)和羰基(CVO)基团伸缩振动峰的存在,表明AN和AM单体发生了共聚合反应。AM单体的引入破坏了PAN共聚物的规整性,其结晶度整体上呈现降低趋势。不同DSC放热峰起始温度(Ti)和放热速率(ΔH/ΔT)先降低后升高的变化趋势表明,AM单体较好地缓和了PAN聚合物的放热反应。
Abstract
Acrylonitrile/acrylamide (AN/AM) copolymer with high molecular weight was synthesized by a precipitation polymerization technology using a single water-soluble inorganic ammonium salt ammonium persulfate (APS) as initiator in a mixed solvent of water/dimethylformamide (H2O/DMF).The effects of mixed solvent ratio and monomer ratio on polymerization conversion and viscosity average molecular weight of PAN products at high H2O content were mainly investigated.And then structure and properties of various PAN polymers were characterized by element analyzer (EA),fourier transform infrared spectroscopy (FT-IR),wide-angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC).It was shown that with the increase of H2O content in the mixed solvent,the viscosity average molecular weight of PAN decreased gradually,and the conversion rate of polymerization increased first and then decreases.With the increase of AM comonomer content in the feed,the viscosity average molecular weight and polymerization conversion became higher first and then decreased.Simultaneously,the content of O element in the PAN increased gradually,indicating that the AM unit content in the copolymer increased.And the presence of stretching vibration peaks of nitrile (C≡N) and carbonyl (CO) groups in the FT-IR spectrum suggested that the AN and AM monomers had undergone copolymerization.As the introduction of AM monomer,the regularity of different PAN copolymers were destroyed,whose crystallinity had a whole tendency to decrease.The initial temperature Ti and the exothermic rate ΔH/ΔT of different DSC exothermic peaks had the changing trend of first decrease and succedent increase,indicating that the AM monomer had better moderated the exothermic reactions of PAN polymers.
关键词
丙烯腈
/
丙烯酰胺
/
混合溶剂沉淀聚合
/
过硫酸铵
Key words
acrylonitrile
/
acrylamide
/
mixed solvent precipitation polymerization
/
ammonium persulfate
过硫酸铵引发混合溶剂沉淀法制备丙烯腈/丙烯酰胺共聚物及性能研究[J].
化工新型材料, 2021, 49(11): 136-140 DOI:10.19817/j.cnki.issn 1006-3536.2021.11.029
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基金资助
国家自然科学青年基金项目(51803047);河南省科技厅项目(202102210035);河南省高等学校青年骨干教师培养计划项目(2019GGJS227);河南省高校省级大学生创新创业训练计划项目(S202011765019);河南城建学院校级学术技术带头人项目(YCJXSJSDTR201909)
