PA6熔体中己内酰胺阴离子聚合的研究

发布时间：2018-06-29 10:45

本文选题：阴离子聚合 + 水解聚合　；参考：《浙江理工大学》2016年硕士论文

【摘要】：聚酰胺6(PA6)是一种用途广泛的聚合物材料,作为纤维主要应用于纺织服装、轮胎帘子线等方面,作为五大工程塑料之一,主要应用于机械、化工、通讯等领域。PA6聚合机理分为水解开环聚合与阴离子开环聚合,两者反应条件截然不同,水解聚合为逐步聚合,采用水作为开环剂,并于聚合后期排水以控制分子量;阴离子聚合为连锁聚合,须严格控制水、酸在极低的含量。水解聚合为逐步聚合,产物分子链端不含活性中心;阴离子聚合为活性聚合,具有反应速度快、分子量高的特性。本文结合水解开环聚合与阴离子开环聚合两种聚合机理,以熔体流动性较好的水解聚合PA6为基体,通过添加己内酰胺(CL)单体及阴离子聚合引发剂与活化剂,在PA6基体熔点以上温度反应得到APA6/HPA6复合产物。为确定引发剂与活化剂的用量,以及合适的反应温度与时间,先后进行了静态浇铸与动态混合、常规工业浇铸温度与目标高温下单纯阴离子聚合实验,优化得到适合目标反应的条件。静态浇铸实验表明,以己内酰胺钠(C10)为引发剂,双酰化内酰胺-1,6-己二胺(C20)为活化剂的阴离子聚合体系在常规浇铸温度(160oС)及相对较高的温度(220oС)下均得到了阴离子聚合PA6产物,FT-IR、TGA、DSC等测试结果表明该阴离子聚合助剂体系同样适合较高的反应温度,热稳定性测试表明CL/C10/C20质量比为100/2.0/2.0时,产物小分子失重比例最低,同时考虑后续进行动态混合时助剂可能存在的少量热损失,故同将CL/C10/C20为100/2.5/2.5列为适合比例。采用转矩流变仪混炼平台作为动态混合反应场所,通过一步加料法混合反应得到两种助剂比例、四种反应温度下的阴离子聚合PA6。FT-IR测试表明产物具有典型聚酰胺特征峰,可萃取物含量测试表明单体转化率均在90%左右,热性能测试表明产物中含有不同聚合程度组分,100/2.5/2.5比例产物结晶度较高,单体剩余较少,反应温度过低与过高将影响熔体流动性、体系交联程度,因而选择230oС作为目标反应温度,反应时间不宜过长,视实时扭矩变化而定。按既定助剂比例、温度进行水解聚合PA6熔体中的己内酰胺阴离子聚合实验,同样采用转矩流变仪及一步加料的方式制备水解聚合PA6/阴离子聚合PA6复合产物。FT-IR测试表明复合产物保持聚酰胺的特征峰,DSC测试表明随着己内酰胺初始含量的增加,复合产物结晶度呈下降趋势,结晶峰由窄变宽,熔融温度下降,TGA测试表明己内酰胺含量较高时存在明显的三个热失重阶段,表明阴离子聚合的发生,可萃取物含量测试表明随着己内酰胺含量的减小,转化率呈上升趋势,最高接近50%,相对黏度测试表明转化率最高的样品相对黏度稍高于空白样品。推测聚合体系在转矩流变仪中存在较为严重的热氧降解,端基含量测试表明反应后空白样品羧基含量增加,降解产物影响了原本可能进行至更高程度的阴离子聚合反应,引入与己内酰胺及PA6相容性较差的线性低密度聚乙烯作为对照,同时也对比了未经工业萃取(含8.88%)的水解聚合PA6作为基体时的聚合情况,实时扭矩变化及反应前后己内酰胺含量测试结果表明,存在热氧降解的情况下,PA6与PE熔体作为反应基体时,己内酰胺均未进行高聚合程度的反应,未经工业萃取的水解聚合PA6与对应比例的助剂混合反应后,己内酰胺参与反应比例低于外加己内酰胺的体系,从侧面印证了聚合物热氧降解对己内酰胺阴离子聚合程度的影响。
[Abstract]:Polyamide 6 (PA6) is a widely used polymer material. As a fiber, it is mainly used in textile and clothing, tire cord and other aspects. As one of the five major engineering plastics, the polymerization mechanism of.PA6 is mainly used in mechanical, chemical, communication and other fields, which are divided into hydrolytic open ring polymerization and anionic ring opening polymerization. The reaction conditions are completely different and hydrolyzed. Water is used as an opening agent for polymerization, and water is used as an opening agent, and water is drained to control molecular weight at the later stage of polymerization; anionic polymerization is a chain polymerization which must strictly control water and acid at a very low content. Hydrolysis polymerization is gradually polymerized, the chain end of the product is not containing active center, anions converge to active polymerization, with fast reaction speed and high molecular weight. In this paper, combining the two polymerization mechanisms of hydrolysis open ring polymerization and anionic ring opening polymerization, the APA6/HPA6 composite products are obtained by adding caprolactam (CL) monomer, anionic polymerization initiator and activator by adding caprolactam (CL) monomer and anionic polymerization initiator and activator, to determine the initiator and activator by the two polymerization mechanism of hydrolysis open ring polymerization and anionic ring opening polymerization. Static casting and dynamic mixing were carried out, and the normal industrial casting temperature and the simple anion polymerization under the target high temperature were carried out. The conditions for the target reaction were optimized. The static casting experiment showed that the sodium caprolactam sodium (C10) was used as the initiator, and the diacylated lactam -1,6- hexandiamine (C20) was used as the initiator. The anionic polymerization PA6 products were obtained under the conventional casting temperature (160o) and relatively high temperature (220o). The test results of FT-IR, TGA and DSC showed that the anionic polymerization assistant system was also suitable for higher reaction temperature. The thermal stability test showed that when the mass ratio of CL/C10/C20 was 100/2.0/2.0, it was produced. The weight loss ratio of small molecules is the lowest. At the same time, a small amount of heat loss may exist during the subsequent dynamic mixing, so CL/C10/C20 is the suitable proportion of 100/2.5/2.5. The mixing platform of torque rheometer is used as a dynamic mixing place, and the proportion of two auxiliaries and four kinds of reaction temperatures are obtained by the mixing reaction of one step feeding method. The anionic polymerization PA6.FT-IR test showed that the product had typical peak of polyamide characteristic, and the content test of the extract showed that the conversion rate of the monomer was about 90%. The thermal performance test showed that the product contained different degree of polymerization, the crystallinity of the product of 100/2.5/2.5 was higher, the residue of the monomer was less, the reaction temperature was too low and too high to affect the melting. As the body fluidity and the degree of system crosslinking, 230o is chosen as the target reaction temperature, the reaction time should not be too long, depending on the change of real time torque. The experiment of caprolactam anionic polymerization in the hydrolyzed polymerized PA6 melt is carried out according to the proportion of the established auxiliaries, and the hydrolysis polymerization PA6/ Yin is also prepared by the torque rheometer and one step feeding. The.FT-IR test of the PA6 compound of ionic polymerization showed that the compound product maintained the characteristic peak of polyamide. The DSC test showed that with the increase of the initial content of caprolactam, the crystallinity of the compound product declined, the crystallization peak was narrowed from narrow to the melting temperature, and the melting temperature decreased. The TGA test showed that there were three obvious stages of heat loss when the content of caprolactam was higher. The results showed that the extraction of anionic polymerization showed that with the decrease of the content of caprolactam, the conversion rate was up to 50%, and the relative viscosity test showed that the relative viscosity of the sample with the highest conversion rate was slightly higher than that of the blank sample. The content test showed that the content of the carboxyl group in the blank sample was increased after the reaction, and the degradation products affected the anionic polymerization that might have been higher to a higher degree, and introduced the linear low density polyethylene with poor compatibility with caprolactam and PA6 as the control, and compared the hydrolysis polymerization of PA6 as matrix without industrial extraction (8.88%). The results of polymerization, change of real time torque and the test results of caprolactam content before and after reaction show that when there is thermal oxygen degradation, when PA6 and PE melt are used as reaction matrix, caprolactam does not react to high degree of polymerization, and caprolactam is involved in the reaction without industrial extraction of hydrolytic polymerized PA6 and the corresponding proportions of additives. The effect of thermal degradation of caprolactam on the degree of anionic polymerization of caprolactam was confirmed from the side of the system which was lower than that of caprolactam.
【学位授予单位】：浙江理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O633.22

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