动态硫化PA12/ACM TPV等温结晶动力学研究

利用熔融共混动态硫化的方法制备尼龙12(PA12)/丙烯酸酯橡胶(ACM)热塑性硫化胶(TPV),并研究PA12/ACM TPV和PA12的等温结晶行为。结果表明:PA12/ACM TPV和PA12的等温结晶行为均符合Avrami方程;在相同结晶温度下,PA12/ACM TPV的结晶速率比PA12大;结晶行为对温度依赖性较大。     

PVDF增韧PA6的结构及机理

采用聚偏氟乙烯(PVDF)对尼龙6(PA6)进行共混改性.通过采用不同的PVDF与PA6共混质量比例,研究了PA6/PVDF共混物的结构及性能.通过偏光显微镜和小角散射分析,发现PVDF的存在阻碍了PA6的结晶.通过拉伸试验发现,在PA6中加入PVDF使得PA6/PVDF共混物的拉伸强度、断裂伸长率和拉伸模量增加了.通过红外光谱分析发现,在拉伸前,PA6/PVDF共混物中只存在PVDF的α晶型,而拉伸后,α晶型消失了,与此同时出现PVDF的β晶型,由此得出,拉伸过程中PA6/PVDF共混物中PVDF分散相发生了由α晶型向β晶型的转变.     

动态硫化尼龙12/丙烯酸酯橡胶热塑性硫化胶等温结晶动力学研究

利用熔融共混动态硫化的方法制备尼龙12(PA12)/丙烯酸酯橡胶(ACM)热塑性硫化胶(TPV),并研究PA12/ACM TPV和PA12的等温结晶行为。结果表明:PA12/ACM TPV和PA12的等温结晶行为均符合Avrami方程;在相同结晶温度下,PA12/ACM TPV的结晶速率比PA12大;结晶行为对温度依赖性较大。     

氯化聚乙烯橡胶/丙烯酸酯橡胶共混物相容性的研究

研究氯化聚乙烯橡胶(CM)/丙烯酸酯橡胶(ACM)并用比、共混温度对CM/ACM共混物相容性的影响。结果表明,CM的门尼粘度对温度变化敏感,ACM不敏感,CM和ACM生胶的门尼粘度差值随着温度的升高而变小;随着共混物中CM用量的增大,CM和ACM玻璃化温度(Tg)的差值(ΔTg)逐渐减小,说明相容性和共混物各组分的用量比有关,在CM/ACM并用比为80/20时ΔTg最小;共混温度对CM和ACM的Tg影响不大,共混物拉伸强度随温度升高而增大。当CM/ACM并用比为50/50时,CM的粘度大,为分散相;ACM的粘度小,为连续相。     

超支化聚合物改性PA6的研究

将芳香族超支化聚合物(HBP)与PA6共混、造粒、纺丝,研究PA6/HBP共混体系的结晶性能及纺丝工艺。结果表明:与PA6相比,HBP的加入对PA6的结晶温度和取向度无明显影响,结晶度提高,其晶型发生变化,γ晶型增强,α晶型略有减弱,HBP以加入质量分数为0.05%较好。PA6/HBP共混体系的熔体流动指数较PA6的明显提高,其纺丝温度明显降低,PA6/HBP纤维的断裂强度有所下降。HBP以加入质量分数为0.05%较好。     

PA6/NBR共混体系的性能研究

采用转矩流变仪,在温度为230℃、转速为80 r/min的条件下进行密炼,熔融共混制备不同聚酰胺6(PA6)与丁腈橡胶(NBR)配比的PA6/NBR共混物,通过差示扫描量热仪、热台偏光显微镜、转矩流变仪、电子万能试验机等分析手段研究了PA6与NBR配比对PA6/NBR共混物性能的影响。结果表明,PA6与NBR配比对PA6/NBR共混物的性能有显著的影响;添加NBR后,PA6的结晶温度提高了10℃左右,NBR对PA6具有异相成核作用并显著降低了结晶尺寸;随着NBR含量的增加,PA6结晶度逐渐下降,当NBR增大到80质量份时,PA6/NBR共混物的结晶度由纯PA6的29.30%降至15.21%,导致PA6/NBR共混物拉伸强度和耐溶剂性能逐渐下降。     

PA6/NMA共混物的制备及其性能研究

以聚酰胺6(PA6)为基体、自制N-苯基马来酰亚胺-马来酸酐二元共聚物(NMA)为耐热改性剂,通过熔融共混法制备了PA6//NMA共混材料。并采用差示扫描量热法(DSC)、热重分析(TGA)、热变形温度及力学性能测试等手段研究了NMA用量对PA6/NMA共混物熔融结晶行为、热性能及力学性能的影响。结果表明:随着NMA用量的增加,PA6/NMA共混物的熔融温度、结晶温度、结晶度以及熔融焓均逐渐降低,而且共混物的最大分解温度较纯PA6显著提高;随着NMA用量的增加,PA6/NMA共混物的力学性能及热性能均明显改善,其中当NMA用量为10份时,共混物的弯曲强度、弯曲模量、拉伸强度及热变形温度分别增至113.8 MPa、3 146 MPa、80.4 MPa以及71.5℃,较纯PA6提高了25.1%、31.9%、15.7%和27.5%;另外,随着NMA用量的增加,共混物的熔体流动速率(MFR)大幅下降,其中当NMA用量增至10份时,共混物的MFR降至5.3 g/10min。     

金属离子配位作用下PA6的受限结晶

采用熔融共混法,制备了聚酰胺6/氯化钙(PA6/CaCl2)复合材料。通过差示扫描量热法(DSC)、X射线衍射法(XRD)研究了PA6基体在受限条件下的非等温结晶及晶型转变行为。结果表明:金属离子Ca2+与酰胺基团的络合配位作用使PA6/CaCl2复合材料中PA6的结晶行为和结晶度受到了限制。随着CaCl2含量的增加,PA6的结晶度、结晶峰温度、熔融峰温度逐渐降低,结晶速率减小,结晶半峰宽增大,当CaCl2的含量大于8%时,PA6变为无定形态;此外,CaCl2的引入有利于PA6中α晶的生成。     

PA 6在受限条件下的非等温结晶行为

采用共混的方法制备了聚酰胺（PA）6,羧基丁苯粉末橡胶新型热塑性弹性体。通过差示扫描量热法研究了该弹性体中PA6基体在受限条件下的非等温结晶行为。研究发现,羧基丁苯粉末橡胶对PA6具有异相成核作用,可提高PA6的结晶温度和结晶速率;PA6在受限条件下有利于生成γ晶型,且随着羧基丁苯粉末橡胶含量以及吸收剂量的提高,更易生成γ晶型。     

TLCPa对PA 6/PA 66相容性及结晶行为的影响

采用溶液共混法制备了聚酰胺6(PA 6)／聚酰胺66(PA 66)/热致聚酰胺液晶(TLCPa)共混物,分析了TLCPa对PA 6／PA 66相容性及结晶行为的影响。差示扫描量热法分析表明,TLCPa的加入改善了PA 6和PA 66之间的相容性,PA 6／PA 66共混物结晶受到抑制;傅里叶变换红外光谱研究表明,TLCPa和PA 6、PA 66分子间形成了大量的分子间氢键,是TLCPa改善共混物相容性的主要原因;广角X射线衍射分析表明,TLCPa的加入没有影响共混物的晶型结构,当w(TLCPa)大于10％时,共混物的结晶度明显下降。     

尼龙6/丙烯酸酯橡胶热塑性弹性体非等温结晶动力学

采用动态硫化法制备尼龙6/丙烯酸酯橡胶热塑性弹性体(PA6/ACM TPE),通过差示扫描量热仪研究了PA6和PA6/ACM TPE在5种不同冷却速率下的结晶过程,并分别用Jezirony法、Ozawa法以及Mo法分析了PA6和PA6/ACM TPE的非等温结晶动力学.结果显示,冷却速率越大,PA6和PA6/ACM T...     

EBA-g-MAH共聚物增容PA6/ABS共混体系的聚集态结构与性能

通过熔融共混法制备了EBA-g-MAH增容PA6/ABS共混物,采用FTIR、SEM、DSC等测试了EBA-g-MAH对PA6/ABS共混物的增容作用;并讨论了EBA-g-MAH对PA6/ABS共混物的结晶性、力学性能及吸水率的影响。研究结果表明:EBA-g-MAH与PA6发生化学反应所生成的接枝物对PA6/ABS共混物有较好的增容作用,使分散相尺寸明显减小;PA6/ABS共混物的冲击强度得到很大的提高,比纯PA6提高430%,吸水性也得到改善,但是拉伸强度有所降低。DSC研究表明:EBA-g-MAH的加入抑制了PA6/ABS共混物中PA6的结晶,使PA6结晶度降低。     

Nonisothermal crystallization kinetics of polyamide 6 and ethylene‐co‐butyl acrylate blends

The nonisothermal melt‐crystallization behavior of PA6 and EBA blends at varying EBA content was investigated using differential scanning calorimetry at different scanning rates. Several macrokinetic models such as Avrami, Jeziorny, Ozawa, Liu, Ziabicki, and Tobin were applied to analyze the crystallization behavior thoroughly under nonisothermal conditions. The Avrami and Tobin model predicted that, for pure PA6 and PA6/EBA blends, simultaneous growth of all forms of crystal structures such as fibrillar, disc‐like, and spherulitic proceeds at an increasing nucleation rate. However, when applied to blends for isothermal crystallization, the Avrami model predicted that the crystallization process is diffusion‐controlled for pure PA6 and PA6/EBA blend containing higher content of EBA (50 phr), where the nylon‐6 chains were able to diffuse freely to crystallize under isothermal conditions. Liu model predicted that, at unit crystallization time, a higher cooling rate should be used to obtain a higher degree of crystallinity for both PA6 and PA6/EBA blends. The kinetic crystallizability of PA6 in the blends calculated using Ziabicki's approach varies depending upon the nucleation density and PA6‐rich regions present in the blend compositions. Nucleation activity of the blends estimated by Dobreva and Gutzowa method reveals that the EBA particles are inert at lower concentrations of EBA and do not act as nucleating agent for PA6 molecules in the blends. The activation energy of nonisothermal crystallization, calculated using Augis–Bennett, Kissinger, and Takhor methods indicated that the activation energy is slightly lower for the blends when compared to the neat PA6. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

EPDM接枝共聚物对MXD6/PA6/EPDM共混物性能的影响

以马来酸酐接枝三元乙丙橡胶（EPDM-g-MAH）为反应性增容剂,通过熔融共混制得聚间苯二甲胺己二酸/聚酰胺6/三元乙丙橡胶（MXD6/PA6/EPDM）共混物。采用Molau实验研究了共混物的相容性,利用哈克转矩流变仪、差示扫描量热仪、偏光显微镜和热重分析仪等研究了MXD6/PA6/EPDM共混物的流变性能、熔融行为、结晶行为以及耐热性能。结果表明,由于EPDM-g-MAH的引入,共混物的平衡扭矩增大,PA6相与EPDM相界面黏附力明显提高;EPDM-g-MAH的引入导致共混物的球晶形貌规整性变差,成核密度下降,结晶速率减慢;随着EPDM含量的增加,共混物的玻璃化转变温度（Tg）和熔融温度（Tm）均呈下降趋势;EPDM-g-MAH的引入提高了共混物的热稳定性。     

HDPE-g-MAH对PA6/UHMWPE共混合金力学性能及结晶行为的影响

采用HDPE-g-MAH作为相容剂来增容PA6/UHMWPE共混合金。结果表明:在熔融共混过程中HDPE-g-MAH和PA6发生化学反应,生成的接枝聚合物对PA6/UHMWPE产生增容作用。加入HDPE-g-MAH共混体系的界面形态和力学性能均有较大的改善,吸水率也有所下降。通过Mo-lau实验I、R、SEM观察来研究其在熔融共混过程对PA6/UHMWPE的反应增容作用。采用DSC实验对PA6/UHMWPE共混合金进行了结晶性能测试,随着HDPE-g-MAH用量的增加,UHMWPE结晶度增加,而PA6的结晶度降低。     

Crystallization of polyamide 56/polyamide 66 blends: Non‐isothermal crystallization kinetics

The non‐isothermal crystallization behaviors of PA56, PA66, and PA56/PA66 blends were studied by differential scanning calorimetry. The Jeziorny and Mo's methods were used to analyze their non‐isothermal crystallization kinetics. The results indicated that Mo's method was better to describe the experimental data in this work. The crystallization rate of PA56 was much slower than that of PA66. The crystallization rate of PA56/PA66 blend was speeded up significantly with the increasing PA66 content when the PA66 content was less than 30 wt %. Further increase in the PA66 content only leads to relatively less increase of the crystallization rate in the PA56/PA66 blends. Activation energies have been determined with Friedman method. The activation energy of PA56/PA66 blends is decreased and lower than that of PA56. PA66 may play a role of nucleating agent toward PA56 to make it crystallize more easily in PA56/PA66 blends. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46409.     

Morphology and Thermal Behavior of MCPA6/SAN Blends Prepared by Anionic Ring-Opening Polymerization of ε-caprolactam

Summary In this article, a series of blends of monomer casting polyamide 6 and styrene-co-acrylonitrile (MCPA6/SAN) were prepared by in situ anionic ring-opening polymerization of ε-caprolactam (CL). Their morphology and thermal behaviors were investigated by means of scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and wide-angle x-ray diffraction (WAXD), respectively. The SAN phase had much finer domain in MCPA6/SAN than that in the polyamide6/SAN (PA6/SAN) blends prepared by melt blending of PA6 and SAN. All the melting and crystallization parameters of MCPA6/SAN blends decreased gradually with the increase of SAN content, while the melting temperature was almost unchanged. These results were due to the hydrolysis reaction of SAN occurred during the anionic polymerization of ε-caprolactam (CL). In addition, WAXD results showed that only α crystal forms existed in the MCPA6/SAN blends.     

尼龙6/聚酯(PET)共混体系结晶相分离的研究

用差示扫描量热（ＤＳＣ）考察尼龙６／聚酯（ＰＥＴ）共混体系的结晶行为，表明是结晶相分离的。不同条件下，结晶相分离的过程和形成的结晶态不同，反映在热行为上，如熔融过程和相应特征参数值，便随着处理的条件、组成比等而改变。研究结果还表明，当尼龙６组分的质量分数Ｗ ＰＡ－６＜ ０．１ 时，它被ＰＥＴ 阻隔而不再结晶，因两者形成部分氢键，酯基对尼龙６ 结晶影响的结果，尼龙６／聚酯（ＰＥＴ）共混体系中尼龙６ 的熔融峰温，随组成比的变化呈现波浪形曲线。     

PAG原位增容PP/PA6共混物的非等温结晶动力学

用差示扫描量热法研究了聚丙烯（PP）、聚酰胺6(PA6)以及用α-甲基苯乙烯（AMS）和甲基丙烯酸缩水甘油酯(GMA)的低相对分子质量共聚物(PAG)原位增容的PP/PA6共混物的非等温结晶动力学,采用修正Avrami方程的Jeziorny法对所得数据进行了处理。结果表明,与对比样PP/PA6相比,加入增容剂PAG后,共混体系中PP和PA6两相的结晶峰温Tp和结晶热焓 H均有所降低,而半结晶时间t1/2则有所延长,表明PAG的加入使共混体系两相大分子链的活动性受到了阻碍,导致其结晶困难;在2.5～40.0 ℃/min的降温速率范围内,修正的Avrami模型能很好地描述PP、PA6、PP/PA6及PAG增容PP/PA6共混物的非等温结晶过程。