苯乙烯-丙烯等规立构嵌段共聚物(iPS-b-iPP)的非等温结晶动力学的研究

用DSC法研究了苯乙烯-丙烯等规立构嵌段共聚物的非等温结晶动力学。结果表明:冷却速率在5～20℃/min范围内,共聚物的非等温结晶动力学参数能很好地符合Avrami动力学方程,非等温结晶速率常数与冷却速率有关,动力学结晶能力则同时受到冷却速率和共聚物组成比的影响。文中还讨论了在非等温结晶条件下共聚物的结晶成核和生长方式与共聚物组成和结构的关系。联合Avrami方程和Ozawa方程推导的非等温结晶动力学方程较好地描述了iPS-b-iPP嵌段共聚物的非等温结晶动力学过程。     

聚乙交酯非等温结晶行为研究

利用差示量热扫描热分析仪(DSC)测得了不同降温速率下聚乙交酯(PGA)的非等温结晶的温度-热焓曲线。分别通过Ozawa法、Jeziorny法和莫志深法对PGA的非等温结晶机理进行了分析。Ozawa法结果表明:在给定的温度范围内,Ozawa法并不适用于描述PGA的非等温结晶行为;Jeziorny法结果表明:不同降温速率下,PGA结晶过程的Avrami指数(n)接近4,PGA非等温结晶为均相成核、晶粒三维增长的过程;莫志深法结果表明:Avrami指数与Ozawa指数的比值(a)基本无变化,动力学参数f(T)随降温速率增加逐渐增大,即在更快的降温速率下,PGA结晶更充分,可获得更高的结晶度。通过Kissinger方程计算得到的PGA结晶扩散活化能为-66.9kJ/mol。     

聚2-吡咯烷酮的非等温结晶动力学

用差示量热扫描热分析仪(DSC)测试了不同降温速率下聚2-吡咯烷酮(PPD)样品的温度-热焓曲线,样品黏均分子量为2.2×10~4,熔点为272℃。采用Jeziorny法、Ozawa法和莫志深法分析了PPD的非等温结晶动力学。结果表明,在给定降温速率范围内,Ozawa法不适用于描述PPD的非等温结晶动力学过程,Jeziorny法只适用于描述PPD的主结晶阶段,而莫志深法能很好地描述整个结晶过程。Jeziorny法处理结果表明,PPD主结晶阶段的Avrami指数(n)为1.68~1.78,晶体生长为准二维生长。莫志深法处理结果表明,在单位结晶时间里达到某一相对结晶度所需的降温速率随相对结晶度的增加而增大。用Kissinger方程求得PPD的非等温结晶活化能为-31.9kJ/mol。     

PA6T的非等温结晶动力学

采用示差扫描量热仪(DSC)考察了PA6T的非等温熔融结晶过程,分别采用Avrami方程、Ozawa方程及Mo提出的新方程对PA6T的非等温动力学数据进行比较分析,计算了相关非等温结晶动力学参数和非等温结晶活化能。结果表明:对于PA6T,用Mo法处理得到的结果更理想。     

稀土发光聚己内酰胺的结晶行为研究

以原位复合方法合成的稀土发光聚己内酰胺（PA6）为研究对象,用差示扫描量热仪（DSC）研究了其结晶行为.结果表明：在聚合过程中,稀土荧光粉具有促进γ晶型生成的作用,同时影响结晶度和结晶动力学.采用修正Avrami方程的Jeziorny法处理非等温结晶动力学,结果表明,荧光粉含量大于5%时,荧光粉对PA6有加速结晶作用.     

去氢枞酸类成核剂改性聚丙烯的非等温结晶动力学研究

对以去氢枞酸盐为成核剂的聚丙烯非等温结晶动力学进行了研究，用修正Avrami方程的Jexiorny法和莫志深法进行处理。结果表明：修正Avrami方程的Jeziorny方法和莫志深法都适用于去氢枞酸类成核剂改性的聚丙烯的非等温结晶动力学。在同样的降温速率下纯聚丙烯的t1/2比成核聚丙烯的t1／2要长，当降温速率为20K/min时，纯聚丙烯和成核聚丙烯的t1/2分别为0．78min和0．51min。同时从莫志深法得到的F(T)结果可以看出，达到相同的结晶度时纯聚丙烯所需的降温速率要大于成核聚丙烯所需的降温速率，说明成核剂的加入提高了聚丙烯的结晶速率。从Jeziorny法求出的纯聚丙烯和成核聚丙烯的Avrami指数分别为4．46和2．77，表明成核剂改变了聚丙烯的结晶成核和生长方式。     

聚丙烯/纳米蒙脱土复合材料的结晶动力学研究

采用热分析方法，研究了聚丙烯／纳米蒙脱土复合材料（PP／CLAY）的等温结晶行为，并分别用Avrami方程和赵志英方法对所得数据进行了分析，研究结果表明，纳米蒙脱土微粒对聚丙烯等温和非等温结晶行为均有不同程度的影响，可提高聚丙烯的结晶速率并改善结晶结构。     

低密度聚乙烯/乙丙烯三元共聚(LDPE/EPO)共混体系的结晶动力学

用DSC方法研究了LDPE/EPO共混体系的等温及非等温结晶动力学,对LDPE/EPO共混体系的等温结晶动力学研究表明,共混物是三维生长的异相成核,共混物在各个结晶温度下的结晶过程都是以方式K_g(Ⅱ)进行的.采用联系Avrami方程和Ozawa方程导出的新非等温结晶动力学方程,处理了LDPE/EPO共混体系,得到了非等温结晶过程的一些基本参数,新方程很好地描述了此共混体系的非等温结晶动力学过程.     

PET/PEN/DBS共混物非等温结晶动力学研究

采用DSC方法, 用修正的Avrami, Ozawa, Ziabicki宏观动力学模型描述PET/PEN/DBS[PET: 聚对苯二甲酸乙二醇酯; PEN: 聚2,6-萘二甲酸乙二醇酯; DBS: 1,3∶2,4-二(亚苄基)-D山梨醇]共混物的非等温熔融结晶过程, 研究结果表明, 修正的Avrami模型能很好地描述此共混物非等温结晶过程. 冷却速率在5-20 ℃/min范围内, Ozawa方程能很好地描述初期结晶过程, 但结晶后期由于忽略次级结晶而不适宜. 由Ziabicki结晶动力学参数可知, 该共混物的结晶随着成核剂DBS含量的增加而降低, 结晶速率随着成核剂DBS含量的增加而提高. 在非等温结晶条件下, 共混物结晶同时受到冷却速率和共混物组成的影响, 与共混物非等温结晶过程的有效能垒分析结果基本一致.     

反式-/顺式-1,4-聚异戊二烯共混体系的结晶动力学

采用差示扫描量热(DSC)法对反式-/顺式-1,4-聚异戊二烯共混体系的等温及非等温结晶动力学进行了研究,分别采用Avrami方程和莫志深法对其动力学参数进行了解析.研究结果表明,在反式-/顺式-1,4-聚异戊二烯共混体系的等温及非等温结晶过程中,顺式-1,4-聚异戊二烯(CPI)组分的存在会降低反式-1,4-聚异戊二烯(TPI)组分的结晶速率;在等温结晶过程中,CPI组分会提高TPI组分自身的结晶度;而非等温结晶过程中,CPI则提高了共混物中β晶型的相对含量.     

Effect of multi-walled carbon nanotubes on non-isothermal crystallization kinetics of polyamide 6

The non-isothermal crystallization behaviors of multi-walled carbon nanotubes (MWNTs)/polyamide 6 (PA6) composites were investigated by differential scanning calorimetry (DSC). Three methods, namely, Avrami, Ozawa and Mo, were carried out to analyze the non-isothermal crystallization data. The results showed that the MWNTs in PA6 acted as effective nucleation agents. However the crystallization rate of composites obtained was lower than that of the neat PA6. It is indicated that the presence of MWNTs influenced the mechanism of nucleation and the growth of PA6 crystallites.     

用DSC研究阻燃PET的结晶性和结晶动力学

<正> 聚对苯二甲酸乙二酯(PET)是一种熔点较高的结晶性聚合物,其结晶性和结晶动力学已得到了广泛的研究。我们最近合成的一种含磷聚合物(或齐聚物)聚苯基磷酸二苯砜酯(PSPPP),可作为PET纺丝较为理想的阻燃剂。当PET中添加5wt％的这种阻燃剂时,其极限氧指数可达到30。然而,有关这种阻燃剂的加入对PET结晶特性的影响方面的研究鲜见报道。本文用DSC方法研究了阻燃剂添加量的多少对PET结晶程度的影响,并且对纺制阻燃PET纤维的实用添加量5wt％的试样进行了结晶动力学研究。     

一种研究聚合物非等温结晶动力学的方法

作者基于多年对聚合物结晶动力学方面研究的工作积累,联合Avrami方程和Ozawa方程,提出了一种研究聚合物非等温结晶动力学的新方法.该方法既克服了使用Ozawa方程所获得的数据点过少,常常出现非线性,不能获得可靠的动力学参数的缺点,又克服了使用经Jeziorny修正的Avrami方程所获得的表观Avrami指数无法准确预测非等温过程成核生长机理的缺点.该方法已成功用于多种聚合物体系,被国内外学者引用数百次,已成为研究聚合物非等温结晶动力学一种有效方法.     

Effect of Electron Beam Irradiation on the Kinetics of Non-isothermal Crystallization of Nylon 66

The non-isothermal crystallization kinetics was studied by differential scanning calorimetric analysis on nylon 66 and e-beam irradiated nylon 66 at different cooling rates. The Modified Avrami equation, the Ozawa equation and the Combined Avrami-Ozawa equation were applied to study the kinetics of non-isothermal crystallization of nylon 66. The crystallization behavior of pristine nylon 66 polymer was compared with that of e-beam irradiated nylon 66 and observed that the kinetics of non-isothermal crystallization of nylon66 was affected largely upon e-beam irradiation. E-beam irradiation not only decreased the crystallization temperature of nylon 66, but influenced the mechanism of nucleation and crystal growth and reduced the overall crystallization rate of nylon 66 also. The crystallization activation energy calculated by the Kissinger method for irradiated nylon 66 was lower than that of pristine nylon 66.     

尼龙-1010非等温结晶动力学

<正> 尼龙-1010是我国独创的工程塑料品种,已被较广泛地应用于精密机械零件、仪表制造、家用电器、航空等方面。有关尼龙-1010的基础研究大多在我国学者中间进行,由于在实际加工生产过程中,如通常的融熔纺丝、注射、模压等工艺均是在非等温条件下进行,有关它的非等温结晶动力学尚未见报道,本文用几种理论方法对尼龙-1010的非等温结晶动力学过程进行研究。     

PLLA-PEG共聚物的非等温结晶行为

采用熔融共聚法制备PLLA-PEG嵌段共聚物, 用WAXD和DSC方法研究其结晶行为, 并用Avrami方程的Jeziorny修正分析了非等温结晶动力学行为. 结果表明, PLLA结晶明显, 而PEG结晶难以观察到, PEG的柔性能促进PLLA结晶. PEG分子量的增加和投料量的增加都能使得结晶温度升高, 结晶度增大, 结晶速度加快.     

Non-isothermal crystallization behavior of polypropylene with nucleating agents and nano-calcium carbonate

The non-isothermal crystallization kinetics of isotactic polypropylene (iPP) and nucleated iPP was investigated by DSC. The crystalline morphology of iPP was observed by polarized light microscopy. It was found that the crystallization rate increased with the addition of nanometer-scale calcium carbonate (nm-CaCO₃) particles. The addition of dibenzylidene sorbitol (DBS) could greatly reduce the spherulite size of iPP. The crystallization temperature for the iPP with DBS was higher than for non-nucleated iPP. DBS was an effective nucleating agent for iPP. The results of measurements suggested that there was a coordinated action to the crystallization of iPP when the organic nucleating agents (DBS) and nm-CaCO₃ were added to iPP together. Comparison to the modified Avrami equation and Ozawa equation, another method—Mo’s method can describe the non-isothermal crystallization behavior of iPP and nucleated iPP more satisfactorily.     

Isothermal and non-isothermal crystallization kinetics of branched and partially crosslinked PET

The crystallization kinetics of branched and partially crosslinked poly(ethylene terephthalate) (PET), prepared using trimethyl trimellitate as branching agent was studied using DSC and WAXD. Crystallization rates were retarded with increasing branching agent content. Avrami equation was used in the isothermal crystallization, while for the non-isothermal process the Ozawa model was applied. Isothermal crystallization half-times increased with branching agent content and crystallization peak temperatures during cooling, decreased. WAXD showed big broadening and reduced degree of crystallinity compared to the neat polyester. Though, the crystal lattice parameters did not seem to alter, crystal size reduction was evidenced.