高结晶性PET玻纤增强材料的研究

研究了聚对苯二甲酸乙二醇酯(PET)增强体系中,原料黏度、成核剂以及结晶促进剂对材料结晶性能的影响,并通过力学性能、热性能及DSC分析不同体系中PET的结晶性能。结果表明,特性黏数0.66 dL/g的PET原料结晶最佳,不同种类成核剂中高分子成核剂Aclyn 285是最佳成核剂,添加结晶促进剂PEG400后显著提高PET的晶体生长速度,所获PET材料结晶完善,DSC图中冷结晶峰消失。     

成核剂对不同特性粘数PET结晶性能的影响

研究了新型复合成核剂水滑石(HT)／离聚物(Surlyn8920)／聚乙二醇(PEG)对不同特性粘数聚对苯二甲酸乙二醇酯(PET)非等温结晶性能的影响。通过差示扫描量热仪测试了PET的结晶峰温度T_(mc)和熔融峰温度(T_m)。结果表明,复合成核剂各组分及PET的质量比为0.5:3.0:3.0:100.0时,各种PET的过冷度(T_m-T_(mc))均显著减少．半结晶时间(1gt_(1／2))也明显降低。而且,复合成核剂对不同特性粘数PET结晶性能的改善是一致的。     

复合成核剂对PET结晶性能的影响

设计了改性蒙脱土(MMT)/耐高温润滑剂和改性MMT/耐高温润滑剂/离子聚合物两个系列复合成核剂,利用熔融共混法制备聚对苯二甲酸乙二酯(PET)/复合成核剂复合体系。运用差示扫描量热分析仪、偏光显微镜、X射线衍射仪对复合体系的结晶性能进行表征。结果表明,耐高温润滑剂在一定程度上改善了改性MMT在PET中的分散性,使改性MMT的异相成核效果更为明显;当改性MMT、耐高温润滑剂的添加量均为1份时,使PET的结晶峰温度升至213.32℃,冷结晶峰温度降低了4.75℃,冷结晶峰明显减弱,结晶速率加快。另一方面,离子聚合物的引入,使PET的结晶峰温度进一步升高到216.75~219.25℃,冷结晶峰温度降低了5.71~11.85℃,冷结晶峰进一步减弱,半峰宽变得更窄,对PET结晶性能的改善更为显著,尤其是改性MMT/耐高温润滑剂/氧化聚乙烯蜡复合成核剂对PET结晶性能的改善最为全面。此外,两个系列复合成核剂都起到了细化晶粒的作用,形成微晶,并且对PET的晶型基本无影响。     

复配型结晶成核剂对PET结晶行为的影响

制备了以聚对苯二甲酸乙二醇酯（PET）为基体的复配型PET结晶成核剂母料——Nu-1；利用12SC研究了不同添加量的Nu-1对PET结晶行为的影响；对比了该成核剂与科莱恩公司的101和杜邦公司的Surlyn对PET结晶行为的影响。结果表明：Nu-1的加入可以有效促进PET结晶的成核速率，随着添加量从2％升高到5％，PET的结晶速率明显提高。在添加量相同时，Nu-1对PET结晶的促进作用接近101和Surlyn。     

HT／Surlyn／PEG复合成核剂对PET结晶性能的影响

研究了水滑石(HT)/离子键聚合物(Surlyn)/聚乙二醇(PEG)复合成核剂对聚对苯二甲酸乙二醇酯(PET)非等温结晶性能的影响。通过正交实验选择最佳复合成核剂配方。差示扫描量热分析表明,HT/Surlyn/PEG复合成核剂各组分与PET的质量比为0．5/3/3/100时,PET的结晶温度提高,半结晶时间明显减少,说明PET的成核能力提高,结晶能力增强,结晶速率加快；同时,结晶放热焓和熔融吸热焓增加,说明PET的结晶度得到提高。     

PET/GF复合材料的制备及性能研究

制备了结晶速率快、力学性能优异的玻纤增强聚对苯二甲酸乙二酯（PET／GF）．研究了基体树脂、结晶成核剂、复合结晶促进刑对PET／GF结晶性能和力学性能的影响,结果表明,结晶成核剂和复合结晶促进剂的加入明显降低了PET／GF的玻璃化转变温度,扩大了结晶温度范围,提高了;中击强度。PET／GF的各项性能达到或超过了国内外同类产品的水平.     

聚乳酸的等温结晶研究

研究了成核剂SX,滑石粉（Talc）及SX与Talc复合对聚乳酸（PLA）结晶的影响。等温结晶动力学表明,各个体系Avrami参数均在1—2．5之间,为异相成核。SX含量从0．2％（质量分数,下同）增加到0．6％后,结晶速率大大提高,结晶半周期tln为0．65min,并且随着等温结晶温度的减小,t1/2减小。Talc含量变化对提高PLA结晶速率没有明显影响。SX是比Talc更高效的成核剂,当其添加到0．6％,120oC时等温t1/2为0．65min,远小于添加6％Talc的。SX与Talc有协同作用,添加0．2％SX＋4％Talc的样品t1,2达到0．10min。     

中低粘度PET非等温结晶性能研究

运用差示扫描量热仪研究了不同特性粘数(0.55~0.70 d L/g)的PET非等温冷结晶和熔融结晶过程。结果表明,随着特性粘数降低,PET样品消除热历史后的冷结晶起始温度θo和峰温θp向低温区偏移,半结晶时间t1/2延长,特性粘数在0.617 d L/g以下,易形成完善的大尺寸结晶;PET熔融结晶温度呈上升趋势,熔融结晶t1/2降低,结晶速率增加,当特性粘数大于0.657 d L/g时,t1/2和Avrami指数n明显增加,不利于拉膜时铸片的均匀性。     

PP/PET/POE-g-MAH共混合金的等温结晶动力学特性

应用差示扫描量热法(DSC),研究了加入不同份数增容剂POE-g-MAH的PP/PET共混合金及纯PP的等温结晶行为,采用Avrami方程处理等温结晶过程,计算结晶动力学参数。结果表明,随着结晶温度的升高各体系的结晶速率下降,结晶速率常数K、n降低,半结晶时间t1/2延长。同一温度下PET有明显的异相成核作用,提高了基体的结晶速率;POE-g-MAH的加入降低了基体的结晶速率,并且随着增容剂含量的增加,基体的结晶速率逐渐下降。纯PP的等温结晶过程具有异相成核与均相成核的机理,共混合金的等温结晶过程属于异相成核机理。     

一种新型复合成核剂对PET结晶性能和摩尔质量的影响

采用双螺杆挤出机,以熔融挤出法制备了含不同结晶成核剂的聚对苯二甲酸乙二醇酯(PET)样品.利用差示扫描昔热法(DSC)、黏度法研究了成核剂对PET结晶行为和摩尔质量的影响,并对比了复合成核剂(苯甲酸钠/酯交换剂A)与常用成核剂苯甲酸钠及乙烯/甲基丙烯酸共聚物的离聚物(Surlyn)对PET结晶行为和摩尔质量的影响.研究结果表明:在成核能力方面,复合成核剂的效果优于苯甲酸钠和Surlyn;同时,复合成核剂的加入还能有效地降低PET摩尔质馈的损失程度,加入复合成核剂的PET摩尔质量明显高于加入苯甲酸钠的PET样品,与加入Surlyn成核剂的PET样品摩尔质量接近.     

Research on synthesis and thermal properties of poly(ethylene terephthalate) sulfonate group containing ionomer

In order to solve the poor nucleation ability and slow crystallization rate of polyethylene terephthalate (PET), we propose a new strategy to prepare PET with self-nucleation ability based on the mechanism of mutual attraction of ions. In this study, a hydroxyl-terminated sulfonate monomer, sulfonated 1,4-butanediol (SBDO) without rigid structure was synthesized as nucleating agent functionalized PET third monomer, and then PET ionomers (PETi) were prepared through melt polycondensation with different contents of SBDO. The half-crystallization time of PETi was sharply decreased in contrast with pure PET and the crystallization temperature was significantly increased from 182.6°C to 210.8°C for PETi1. Due to the high nucleation efficiency of SBDO, the crystallization temperature of PET was significantly increased, avoiding the excessive addition of traditional nucleating agents to deteriorate the mechanical properties of PET. The increased nucleation efficiency was contributed to the aggregation of SBDO induced by the ionic interactions.     

PE-HD/纳米SiO2杂化材料的等温结晶行为的研究

通过熔融接枝反应将乙烯基三甲氧基硅烷接枝到高密度聚乙烯(PE-HD)分子链上,以四乙氧基硅烷为前驱体,加入接枝的PE-HD中,通过溶胶－凝胶法制备了PE-HD/纳米SiO2杂化材料。用差示扫描量热法研究了纳米SiO2 对PE-HD等温结晶行为的影响。结果表明,随着结晶温度的提高,PE-HD和PE-HD/纳米SiO2杂化材料等温结晶峰明显右移,说明结晶所用时间延长,结晶速率下降;纳米SiO2在PE-HD中起到异相成核的作用,使PE-HD/纳米SiO2的结晶速率比PE-HD的大。等温结晶动力学研究表明,随着结晶温度的提高,两种材料的半结晶期都有所延长,且PE-HD/纳米SiO2杂化材料比PE-HD延长的幅度更大。     

成核剂在PET结晶中的应用

介绍了聚合物的结晶理论,在PET中加入成核剂进行共混,可以提高PET的结晶速度。阐述了国内外采用成核剂提高PET结晶速度的研究情况,并指出了适用于PET热熔胶的成核剂种类。     

Effects of hybrid nucleating agents on glass fiber‐reinforced polyethylene terephthalate/polybutylene terephthalate alloy crystallization

In this article, the Surlyn® 8920 and AX 8900 were mixed as hybrid nucleating agents for glass fiber (GF)‐reinforced polyethylene terephthalate (PET)/polybutylene terephthalate (PBT) alloy. The crystallization behaviors on GF‐reinforced PET/PBT alloy with compound nucleating agents of Surlyn® 8920 and AX 8900 were studied by differential scanning calorimeter. The Jeziorny method, Mo method, and Kissinger method were used for studying the non‐isothermal crystallization process of the composite alloys. While single AX 8900 cannot further improve the crystallization properties of the alloy and reduced the crystallization rate, the introduction of Surlyn® 8920 can effectively ameliorate the condition. The results demonstrated the hybrid nucleating agents of Surlyn® 8920 and AX 8900 not only can accelerate crystal growth, but also can significantly reduce the energy barrier, and it has a good effect in the alloy to the nucleation. POLYM. COMPOS. 37:1167–1172, 2016. © 2014 Society of Plastics Engineers     

酰胺类β成核剂对PP R非等温结晶动力学影响

研究了酰胺类β晶型成核剂对无规共聚聚丙烯(PP R)非等温结晶动力学的影响。结果表明,β成核剂提高了PP R的结晶峰温。在相同的冷却速率下,β成核剂改性PP R体系的Zc比纯PP R小,半结晶时间t1/2比纯PP R长;达到相同结晶度时,β成核剂改性PP R体系所需的冷却速率大于纯PP R,这说明β成核剂的加入降低了PP R的结晶速率。莫法可以很好地表征PP R及β成核剂改性PP R体系的非等温结晶行为。     

复合成核剂对PBT结晶行为的影响

采用熔融共混法制备了聚对苯二甲酸丁二醇酯(PBT)和成核剂二苄山梨醇(DBS)或苯甲酸钠(SB)的共混物,通过差示扫描量热仪(DSC)、X射线衍射仪(XRD)、偏光显微镜(PLM)分析了各成核剂对PBT的结晶行为的影响,结果表明:添加任何一种成核剂均能明显改善PBT的结晶行为,即加快结晶速度、提高结晶度、细化晶体及完善晶体形态;其中复合成核剂要明显优于单一成核剂,复合成核剂中SB的影响程度要大于DBS。还采用热重分析(TGA)仪对体系的热性能进行了研究,发现成核剂的加入并未降低体系的热性能。     

二氧化钛含量对PET非等温结晶性能的影响

采用差示扫描量热法研究了不同二氧化钛(Ti O2)含量聚对苯二甲酸乙二醇酯(PET)的非等温冷结晶和熔融结晶性能。结果表明,与纯PET相比,在二氧化钛含量小于2.4%时,消光PET的冷结晶动力学常数Zc基本不变,半结晶时间t1/2略有减小;随着二氧化钛含量的增加,熔融结晶动力学常数Zc逐渐增大、半结晶时间t1/2逐渐减小,结晶速率加快;Avrami指数n先逐渐增大,当二氧化钛含量达到2.4%后又减小。     

Effect of nucleating agents on the crystallization of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate)

The effect of nucleating agents on the crystallization behavior of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) was studied. A differential scanning calorimeter was used to monitor the energy of the crystallization process from the melt and melting behavior. During the crystallization process from the melt, nucleating agent led to an increase in crystallization temperature (T_c) of PHBV compared with that for plain PHBV (without nucleating agent). The melting temperature of PHBV changed little with addition of nucleating agent. However, the areas of two melting peaks changed considerably with added nucleating agent. During isothermal crystallization, dependence of the relative degree of crystallization on time was described by the Avrami equation. The addition of nucleating agent caused an increase in the overall crystallization rate of PHBV, but did not influence the mechanism of nucleation and growth of the PHB crystals. The equilibrium melting temperature of PHBV was determined as 187°C. Analysis of kinetic data according to nucleation theories showed that the increase in crystallization rate of PHBV in the composite is due to the decrease in surface energy of the extremity surface. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2145–2152, 2002     

High Efficiency Nucleating Agents of Polyoxymethylene

In this research, the effects of different kinds of nucleating agents on the crystallization and mechanical properties of polyoxymethylene (POM) were studied, including inorganic, organic, and polymer nucleating agents and their compounds. These properties showed that nanoCaCO₃, sorbitol derivative TMB-5, polyamide PA-4, and compound C-1/polyamide (PA)-4 can make spherulites of POM finer and more perfect, and effectively improve its notched impact toughness, in which the compound C-1/PA-4 displayed more remarkable nucleation effect. The study on the nonisothermal crystallization of POM showed that the crystallization temperature and crystallization growth rate of POM increased when C-1/PA-4 was added. The isothermal crystallization kinetics were also analyzed by the Avrami equation. The addition of C-1/PA-4 can increase the values of the Avrami exponent (n) and crystallization rate constant (k), and reduce the half-time of isothermal crystallization, t_1/2, and the time corresponding to the maximum rate of crystallization, t_P, indicating its remarkable nucleating effect on POM.