环氧树脂扩链PBT研究

选取环氧树脂为扩链剂,以聚对苯二甲酸丁二酯(PBT)熔体在Haake转矩流变仪中的相对转矩变化表征扩链效果,研究了环氧树脂扩链PBT过程中,扩链剂的选择、扩链剂用量、反应条件、扩链剂联用、催化剂等对扩链反应的影响.通过实验发现不同类型环氧树脂的扩链效果差异很大,缩水甘油酯类具有最好的扩链效果;随着扩链剂加入量的增加,扩链效果先增加后降低,存在一个最佳的扩链剂加入量;提高反应温度和剪切速率均可加快扩链反应速率;利用邻苯二甲酸酐和环氧类扩链剂联用可以提高扩链反应速率和扩链效果;选取三氧化二锑作为催化剂不仅提高了扩链反应的速率,同时也提高了扩链效果.     

扩链剂联用技术对PET扩链反应的影响

通过对PET扩链反应前后的特性粘数 [η]和羧基 [COOH]值的比较 ,讨论了扩链剂联用条件下不同扩链剂种类、用量以及加入方式对于扩链反应的影响。实验结果表明 ,扩链剂联用对于PET树脂增粘是一个良好的方法 ,可使扩链产物的特性粘数由 0 .62dL g增至 1.1dL g ,同时 [COOH]含量降至很低 ;少量荧光剂同时加入显著改善扩链产物的色泽。在一定的联用条件下扩链产物的热稳定性可保持在较好水平。     

化学反应平衡对聚酯扩链增粘的影响

用化学反应平衡的方法对开环扩链型扩链剂的增粘作用进行理论分析 ,推导出扩链剂用量与聚酯特性粘数变化的关系 ,发现反应平衡常数直接影响扩链效率 ;分析了实现扩链的必要条件和扩链剂的最佳投料量 ;利用推导出的理论关系计算出常见扩链剂参与扩链反应的平衡常数。     

聚酰胺树脂扩链剂及扩链研究

合成２种聚酰胺６的扩链剂,将扩链剂分别用于ＰＡ６的扩链研究,不同的扩链剂适合不同端基的ＰＡ扩链反应。随着扩链剂用量的增加,ＰＡ的特性粘数增加,但扩链剂用量超过一定限度时,扩链效果下降,但ＰＡ６原有的端基量下降。     

双恶唑啉及环氧类扩链剂对TPEE的改性研究

采用恶唑啉类扩链剂和环氧类扩链剂对热塑性聚酯弹性体(TPEE)进行扩链反应,并对扩链产物的特性黏度、熔融指数和力学性能等进行测试和表征,考察了两类扩链剂对TPEE性能的影响,结果表明:在实验范围内当双恶唑啉类扩链剂加入量为0.7%,环氧类扩链剂加入量为0.9%时,所得TPEE的力学性能最好;环氧类扩链剂对TPEE的扩链效果优于双恶唑啉类。     

2，4-甲苯二异氰酸酯扩链合成聚乳酸的研究

采用直接熔融缩聚法先合成相对低分子量的聚乳酸,再以2,4-甲苯二异氰酸酯（TDI）作为扩链剂进行扩链反应。研究了反应时间、温度及扩链剂用量对聚乳酸分子量的影响,并采用IR、DSC及GPC对产物进行表征。实验结果表明：在170℃、0．09MPa下以质量分数10％的TDI作为扩链剂进行扩链反应1．5h,产物分子量提高3．72倍。     

三分钟看懂聚氨酯扩链剂

正聚氨酯扩链剂简介扩链剂:又称链增长剂,是能与线型聚合物链上的官能团反应而使分子链扩展、分子量增大的物质。聚氨酯扩链剂:是指含两个官能团的化合物或二元醇、二元胺、乙醇胺等,通过扩链反应生成线型高分子。扩链剂可用于各种类型的聚氨酯产品中聚氨酯扩链剂功能在聚氨酯材料的合成中,扩链剂具有以下功能:(1)低分子二元或三元或四元化合物能使聚氨酯反应体系迅速地进行扩链和交联。     

环氧树脂对PET扩链的研究

选取环氧树脂为扩链剂,在双螺杆挤出机中对聚对苯二甲酸乙二醇酯(PET)进行熔融扩链,利用熔体质量流动速率(MFR)的变化表征扩链效果.研究了环氧树脂扩链PET时,挤出温度、扩链剂选择、扩链剂用量等对扩链反应的影响,并与扩链剂ADR-4380进行了比较.通过实验发现:不同的挤出温度对扩链效果影响较大;不同类型环氧树脂的扩链效果差异很大;随着扩链剂加入量的增加,扩链效果先增加明显后趋于稳定.与扩链剂ADR-4380相比,缩水甘油酯类环氧的扩链效果更好.     

聚对苯二甲酸乙二醇酯和聚对苯二甲酸丁二醇酯化学扩链反应

本文综述了用于聚对苯二甲酸乙二醇酯，聚对苯二甲酸丁二醇酯化学扩链反应的羧基加成型和羟基加成型扩链剂，以及缩合型扩链反应，羧基加成型扩链反应，羟基加成型扩链反应和羧羟基同时加成型扩链反应，并讨论了扩链反应，反应特性和扩链产物的性能。     

扩链聚对苯二甲酸丁二醇-co-聚己二酸丁二醇酯的合成及表征

采用1,4-丁二醇,对苯二甲酸二甲酯,己二酸合成了聚对苯二甲酸丁二醇-co-聚己二酸丁二醇酯(PBAT)。采用六亚甲基二异氰酸酯作为扩链剂合成了高分子质量的PBAT。研究了扩链反应时间,扩链剂用量对特性黏度的影响;反应温度,扩链剂用量,扩链反应时间对PBAT分子质量、端羧基值的影响。采用核磁共振及红外光谱对聚合物的结构进行了表征。研究结果表明六亚甲基二异氰酸酯可以显著提高PBAT的分子质量,扩链以后力学性能有明显的提高。     

Chain extension of recycled poly(ethylene terephthalate) with 2,2′‐(1,4‐phenylene)bis(2‐oxazoline)

The present work provides improved recycled high molecular weight poly(ethylene terephthalate) (PET) by chain extension using 2,2′‐(1,4‐phenylene)bis(2‐oxazoline) (PBO) as the chain extender. PBO is a very reactive compound toward macromolecules containing carboxyl end groups but not hydroxyl end groups. In the case of PET, where both species are present, for even better results, phthalic anhydride (PA) was added in the initial sample, before the addition of PBO. With this technique, we succeeded in increasing the carboxyl groups by reacting PA with the hydroxyl terminals of the starting polymer. From this modification of the initial PET sample, PBO was proved an even more effective chain extender. So, starting from a recycled PET with intrinsic viscosity [η] = 0.78, which would be [η] = 0.69 after the aforementioned treatment without a chain extender or M̄_n = 19,800, we prepared a PET grade having [η] = 0.85 or M̄_n = 25,600 within about 5 min. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2206–2211, 2000     

Thermo-mechanical behaviour of Polyamide 6 chain extended with 1,1′-Carbonyl-Bis-Caprolactam and 1,3-Phenylene-Bis-2-Oxazoline

A commercial Polyamide 6 (PA6) was melt compounded by using a twin screw extruder with a combination of 1,1′-Carbonyl-Bis-Caprolactam (CBC) and 1,3-Phenylene-Bis-2-Oxazoline (PBO), in order to evaluate their effect on the chain extension behaviour of the resulting materials. An increase of the viscosity values with the chain-extender amount was evidenced by rheological tests on the compounded pellets and relative viscosity measurements on solubilized samples, while the opposite trend was determined increasing the residence time at elevated temperatures. The increase of the molecular weight due to the presence of CBC and PBO was confirmed by the reduction of carboxylic and aminic functionalities evidenced in end group analysis. DSC tests showed a reduction of the melting temperature and of the crystallinity degree proportionally to the chain extender amount. Elastic modulus of the chain-extended materials was similar to that of the corresponding PA6 grades at different molecular weight, while crystallinity drop due to chain extension determined an increase of the strain at break values.     

Enhancing the fracture toughness of glass fiber reinforced polyamide 6,6 composites with the addition of chain extender

The aim of this study is to improve the fracture toughness of glass fiber reinforced polyamide 6,6 (PA6,6) composites by adding 1,4‐phenylene‐bis‐oxazoline (PBO). Essential work of fracture (EWF) analysis was conducted to analyze the effect of chain extender loading level on the fractural properties of composites. Three different wt% levels of chain extender were used (0.5, 1.0, and 2.0 wt%). Results of EWF analysis revealed that 1.0 wt% PBO addition made a great contribution to the fracture energy of the composites. In addition to this, tensile test results showed that while 1.0 wt% PBO addition resulted in a significant increase in tensile strain of composites, 2.0 wt% PBO addition resulted in a significant increase in tensile strength. Dynamic mechanical analysis test results indicated that 2.0 wt% PBO added composites exhibited the highest storage modulus and the lowest tan delta peak height. Morphological analysis results were also coincided with other test results. POLYM. COMPOS., 38:2228–2236, 2017. © 2015 Society of Plastics Engineers     

PET/PBT共混过程中酯交换反应的~(13)CNMR研究

用13C NM R 考察了添加扩链剂进行反应性共混后PET/PBT 的结构变化。在共混初期,检测不到嵌段共聚物的存在,可能与其含量极少有关。随着共混时间的增加,开始出现酯交换反应,且酯交换度随共混时间和温度而增加。扩链剂的加入能促进酯交换反应,但扩链剂的用量对酯交换的影响并不大     

均苯四甲酸二酐改性回收PET的研究

以扩链剂均苯四甲酸二酐对回收PET进行扩链增黏,从特性黏度和端羧基含量的变化考察了其扩链效果,并用DSC研究了不同添加量的扩链剂对回收PET的热性能的影响。结果表明,该扩链剂对回收PET具有良好的扩链增黏效果,并且当其质量分数为1.25%时,回收PET的特性黏度达到0.813 dL/g,可作为工程塑料使用;且影响PET的冷结晶行为。     

PA1010的熔融扩链反应

研究3种扩链剂（环氧树脂、二异氰酸酯和亚磷酸三苯酯）对聚酰胺（PA）的熔融扩链反应。针对具有不同熔体流动指数（MI）的PA材料，得出最佳的扩链剂加入量；并研究了扩链后的PA1010的MI，机械性能和结晶性能。结果表明：以环氧树脂为扩链剂反应活性最高，扩链效果比较明显，但有一定的交联反应发生，导致挤出物熔体破裂；二异氰酸酯在扩链时，由于其在高温下自身会发生化学反应，使扩链效率降低，利用亚磷酸三苯酯在单螺杆挤出机中进行扩链反应，扩链后PA1010的熔体粘度明显增加，MI下降，且交联轻微。     

EAA-g-PEOX对PBT/PP共混体系增容作用的研究

利用ＳＥＭ、ＤＳＣ及力学测试等分析方法,研究了增容剂ＥＡＡ－ｇ－ＰＥＯＸ及扩链剂ＰＢＯ对ＰＢＴ／ＰＰ共混物的形态结构和力学性能的影响。结果表明,ＥＡＡ－ｇ－ＰＥＯＸ明显改善了ＰＰ与ＰＢＴ的相容性,使ＰＰ较均匀地分配在基体中。     

基于异氰酸酯衍生物的聚乳酸熔融扩链工艺、动力学及结构表征

以微波法氧化锌（ZnO）柱撑有机皂石催化丙交酯开环聚合的聚乳酸(PLA)为原料,分别采用二苯基甲烷二异氰酸酯 (MDI)和六亚甲基二异氰酸酯(HDI)进行熔融扩链反应,研究了扩链剂的用量和反应时间对PLA相对分子质量的影响,并对PLA的扩链动力学进行了研究。结果表明,最优的扩链反应工艺参数为：反应温度180 ℃,nNCO：nOH为2.5：1,MDI扩链时间为45 min,HDI扩链时间为30 min;MDI和HDI扩链反应的表观速率常数分别为6.081×10^3、6.98×10^3 g/(mol·min)。     

Chain extension of PA1010 by reactive extrusion by diepoxide 711 and diepoxide TDE85 as chain extenders

The chain extension behaviors of two diepoxides, epoxide TDE85 and 711, were studied to evaluate their coupling effects on polyamide 1010 (PA1010). The former gave better coupling effects and a faster reaction rate. The torque of PA1010 melt increased dramatically with reaction time. The effect of the diepoxy chain extender on the flowability, thermal properties, and mechanical properties of chain‐extended PA1010 was investigated. The melt flow index (MFI) dramatically decreased as the diepoxide was added to PA1010, and the notched Izod impact strength of the chain‐extended products also increased. Furthermore, study on the usage of chain extender showed that there exists an approximate platform on the curve of melt torque versus content of chain extender, beyond which crosslinking may occur. Theoretical analysis of the occurrence of crosslinking was carried out by Flory criterion, which demonstrated that the average amount of functional groups in the chain extension system played a significant role in avoiding crosslinking. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2347–2355, 2004