PC/PET共混体系酯交换反应的研究EI

采用Brabender塑化仪、索氏抽提器、红外光谱(IR)和核磁共振波谱(NMR)初步研完了聚碳酸酯和聚对苯二甲酸乙二醇酯(PC/PET)共混体系在熔融过程中发生的酯交换反应和产物结构。结果表明,PC/PET共混体系在熔融过程中有酯交换反应发生,反应程度与组分含量、熔融温度和共混时间有关。     

PET/PEN扩链反应共混的研究 Ⅰ.共混条件对酯交换及链结构的影响

用1H-NMR方法对PET/PEN在少量扩链剂存在下的反应性共混条件对酯交换反应及序列结构的影响作了系统研究.结果表明,混合时间、温度对酯交换反应有显著的影响.随着时间的增加和温度的提高酯交换程度增加,而导致共聚酯的数均序列长度变短.共混物的组成及少量扩链剂的存在,在某些条件下对酯交换反应及序列结构也显现出较明显的影响.     

PET／PEN扩链反应共混的研究 I．共混条件对酯交换及链结构的影响

用^1H-NMR方法对PET／PEN在少量扩链剂存在下的反应性共混条件对酯交换反应及序列结构的影响作了系统研究。结果表明，混合时间、温度对酯交换反应有显著的影响。随着时间的增加和温度的提高酯交换程度增加，而导致共聚醋的数均序列长度变短。共混物的组成及少量扩链剂的存在，在某些条件下对醋交换反应及序列结构也显现出较明显的影响。     

聚氨酯/磺化聚苯乙烯共混体系的相容性及力学性能

讨论了聚醚型聚氨酯／磺化聚苯乙烯共混体系的相容性和力学性能。结果表明,ＰＵ／ＳＰＳ－９．８３ｍｏｌ％共混体系中存在的离子－离子等特殊相互作用,使组分 容性明显增加,界面状况改善。离子－离子相互作用的增强和组分离子交联结构的形成,使共混物的拉伸强度出现极大值,但也导致了材料的脆性断裂。     

PET/PBT合金的熔融共混及性能

论述了PET/PBT合金的熔融共混理论,包括两种材料熔融共混过程中的相容性、结晶性及酯交换反应:PET/PBT共混体系在非晶区是相容的;加工工艺对共混体系的结晶度影响很大,PET和PBT共混对其结晶过程具有协同效应,可在成型加工时添加成核体系以促进其结晶;酯交换反应会使体系的结晶能力下降。简要讨论了合金的机械性能及不同因素对其影响:合金硬度受体系分子量和淬火时冷却速率的影响,增强合金的弯曲强度可填充改性无机填充剂,合金的缺口敏感性强,缺口冲击强度较低,所以冲击改性常被作为其重要研究对象。PET/PBT合金作为一种工程塑料,现阶段主要应用于汽车领域,未来将在电子电器、机械工业和汽车零部件等领域有着更广泛的应用。     

PET/PEN共混物的结晶与冷结晶性能及其机理

采用双螺杆熔融挤出法制备了聚对苯二甲酸乙二醇酯(PET)/聚2,6-萘二甲酸乙二醇酯(PEN)共混材料,利用差示扫描量热法(DSC)研究了不同质量比的PET/PEN共混物的熔融与结晶性能。研究结果表明,PET/PEN共混物为部分相容的两相结构。在PET和PEN等质量共混时,可能形成部分相容且彼此交叠的两个连续相。冷却过程中两共混组分既各自形成结晶,又存在一定的共结晶。PET和PEN分子及其链段间互相缠绕和相互作用干扰大分子的结晶过程,导致冷却(降温)过程中结晶不完善和结晶度降低。PET/PEN共混物与PET和PEN一样,具有明显的冷结晶倾向。     

聚氨酯／环氧树脂共混物的形态结构及其力学性能

聚氨酯和环氧树脂共混体系，通过固化前后的红外谱图，分析了两者之间的反应；由扫描电镜照片和计算共混体系杨氏模量，都表明两种共混物形成了连续的两种互穿网络结构，共混物中两组分质量比是影响其力学性能的相区尺寸的主要因素，将此共混物作为涂层的抗汽蚀性和冲蚀磨损性都很好。     

聚对苯二甲酸乙二醇酯／聚碳酸酯合金研究进展

评述了近年来聚对苯二甲酸乙二醇酯（PET）／聚碳酸酯（PC）合金研究的最新工作，着重讨论了PET／PC合金酯交换与相容性的关系、第三组分增容PET／PC、PET／PC体系的结晶行为以及PET／PC合金的应用4个方面，并对PET／PC共混物的发展方向进行了展望。     

PET/PLA共混物相容性的分子动力学模拟

采用分子动力学(MD)模拟方法在COMPASS力场下,研究了不同质量比(90/10、70/30、50/50、30/70和10/90)聚对苯二甲酸乙二醇酯(PET)/聚乳酸(PLA)共混物的相容性。研究结果表明,不同比例下共混物的Flory-Huggins相互作用参数(χ)均小于χcritical,可以预测PET与PLA两者具有良好的的相容性。对不同比例的PET/PLA共混物中C-C原子对分子间径向分布函数的分析进一步证明PET/PLA共混物是相容的。通过分析共混物中不同组分羰基上的O和羟基上的H原子对分子间径向分布函数发现,PET和PLA分子链间可以形成C=O…H-O氢键,有利于其共混物形成相容体系。     

PET/PEN扩链反应共混的研究Ⅱ.特性粘度及无规度的变化

对PET／PEN共混体系中共混条件对体系特性粘度的影响作了研究，结果表明，扩链剂的添加，混合温度和时间对[η]有明显的影响，^1H-NMR对共混物无规度的表征表明，体系首先形成嵌段共聚物，随酯交换的进行逐渐向无规共聚物过渡。     

聚碳酸酯/聚(1, 4-环己烷二甲酸- 1, 4-环己烷二甲醇酯)共混物的光学特性及机理分析

采用熔融共混法制备一系列聚碳酸酯(PC)与聚(1, 4-环己烷二甲酸-1, 4-环己烷二甲醇酯)(PCCD)形成的共混物。光学性能测试表明,PC/PCCD共混物具有高透光率、低雾度的光学特征。采用SEM、TEM、DSC、红外光谱及核磁共振等多种手段对PC/PCCD进行研究,以揭示共混物呈现光学透明性的内在机理。结果表明：PC/PCCD在几十纳米尺度下具有均相结构,均相结构是其在宏观上表现高透明性的直接原因; 不同PCCD含量的PC/PCCD共混物均表现出单一玻璃化温度,表明PC和PCCD完全相容。这种均相结构的完全相容,是PC/PCCD共混物呈现高透明性的内在原因。通过进一步分析PCCD和PC相容的机理,发现PC与PCCD熔融共混过程中未发生酯交换反应,PC和PCCD的相容源于结构相似,与是否发生酯交换反应无关。     

聚体Surlyn对PET/PA-6共混物的相容性及形态结构的影响

通过偏光显微镜观察,扫描电镜观察,动态力学分析和广角和Ｘ射线衍射分析,研究了离聚物Ｓｕｒｌｙｎ对ＰＥＴ／ＰＡ－６共浊 相容性及形态结构的影响。     

热致液晶共聚酯酰胺／PET共混物的相容性和形态结构

用溶解度参数预测热致液晶共聚酯酰胺（ＰＥＡ）与聚对苯二甲酸乙二酯（ＰＥＴ）共混物的相容性。采用偏光显微镜、扫描电镜研究其形态结构。结果表明：ＰＥＡ／ＰＥＴ共混物虽然在理论上是热力学相容的，但因ＰＥＡ的热致液晶性，从液晶有序相变为各向同性存在热效应，致使理论预测与实验结果产生偏差。ＰＥＡ／ＰＥＴ共混物呈两相结构，当ＰＥＡ含量少时，两相之间具有一定的相容性。共混物熔体在剪切力作用下，液晶相形成取向微纤     

PET／HDPE共混物的形态结构及力学性能的研究

利用ＩＲ、ＳＥＭ、ＤＳＣ和力学测试等分析方法，研究了熔融接枝高密度聚乙烯（ＨＤＰＥ－ｇ－ＭＡ）和界面改性剂（ＩＭ）对ＰＥＴ／ＨＤＰＥ共混物形态结构、界面偶联状况和力学性能的影响。结果在明，ＨＤＰＥ－ｇ－ＭＡ改善了ＰＥＴ与ＨＤＰＥ的相容性，使ＨＤＰＥ较均匀地分散在ＰＥＴ基体中，但并未检测到ＰＥＴ／ＨＤＰＥ－ｇ－ＭＡ界面有化学反应发生。界面改性剂的作用在于，一方面通过提高ＰＥＴ基体的粘度，并接近ＨＤＰＥ相的粘度而使分散相细化；另一方面通过与ＨＤＰＥ－ｇ－ＭＡ和ＰＥＴ的偶联反应而增强了ＰＥＴ／ＨＤＰＥ－ｇ－ＭＡ界面粘结，从而显著地提高了共混物的抗冲击性能。     

Essential work of fracture testing of PC-rich PET/PC blends with and without transesterification catalysts

0.7 mm sheets of blends of polycarbonate (PC) with polyethylene terephthalate (PET) rich in PC in the presence and absence of three different transesterification catalysts have been obtained using reactive extrusion-calendering processing method in order to evaluate the fracture toughness of these materials applying the essential work of fracture (EWF) approach which has not been previously reported in the literature. The morphology has been characterized by scanning electron microscopy (SEM). In addition, the tensile properties of these materials were determined. There is a decrease on the essential term (w _e) values of PC/PET blends without transesterification catalysts while blends with transesterification catalysts present an increment in comparison with neat PC which may related to the product of the transesterification that plays like an emulsifier/compatibilizing agent to reduce the interfacial tension between the components of the blend and reduce the interfacial tension between the two immiscible or incompatible component phases to get a better fracture behavior. This is confirmed by the tensile test results obtained which demonstrate higher values for E and σ _y in the case of blends with transesterification catalysts compared with neat PC. For non-essential term of fracture (βw _p), blends without catalysts exhibit an increase compared with neat PC by increasing the amount of PET which may due to the lowering of the yielding stress. In contrary, the presence of transesterification catalysts and especially Zn-based shows decrease as a consequence of the restriction that occurred on the movement of PC segments during the transesterification reactions or as a decohesion of the dispersed phase during the test.     

HDPE／PET层状分散合金亚微相态与相容性关系

通过选择相容剂种类及添加量，改变了HDPE/PET共混体系中分散相的尺寸及形态从而获得了以PET为分散相的各种层状分散相态研究了共混体系相容性与相态之间的关系结果表明：PET层化趋势随体系的相容性增大而增强但当相容剂含量超过一定值时，层状分散相态从中心处开始被破坏．根据这一现象，提出了层化相容区的概念     

New aspects of the microstructure of glassy PET/PEN blends as revealed by microhardness

The microhardness of films of poly(ethylene terephthalate) (PET) and poly(ethylene naphthalene-2,6-dicarboxylate) (PEN) blends prepared by co-precipitation from solution followed by melt-pressing and quenching was determined. The miscibility, transesterification and crystallization properties of these blended films were reported previously [1]. The PET/PEN compositions chosen were 10/90, 30/70, 44/56, 60/40, 70/30 and 90/10. The microhardness of films was notably affected by the composition. It is shown that the deviation of microhardness from the additivity law of the single components depends on the time for which the blend was melt-pressed before quenching in ice water. The results are discussed in light of changes occurring from the initial two-phase structure of the single components through the one-phase structure up to the PET-co-PEN obtained by transesterification of the two components. This revised version was published online in November 2006 with corrections to the Cover Date.     

新型sPS/PET/SsPS-K工程塑料合金的性能与表征

制备了新型综合性能优于间规聚苯乙烯（sPS)/聚对苯二甲酸乙二醇酯（PET）的sPS/PET/磺化间规聚苯乙烯钾盐离聚体（SsPS-K)工程塑料合金，当sPS/PET/SsPS-K为85／15／4时，合金的冲击强度最大为11．5kJ/m^2，是纯SPS的3倍，且拉伸强度和弯曲强度依旧较高，耐热性较好，DSC分析表明sPS和PET的熔点几乎不受SsPS-K用量的影响，分别接近各自的纯料，而起始结晶温度和达到最大结晶速率时的温度均提高，另外，PET的结晶速率显著提高，SEM观察到加入SsPS-K后，PET分散相的尺寸减小，且随其用量的增加，分散相尺寸进一步减小和均匀。     

PVC／ABS共混合金的结构与性能

利用透射电镜观察ＰＶＣ／ＡＢＳ共混合金的结构，结合其流变性，机械性能，探讨结构与性能之间的关系。结果表明，ＰＶＣ／ＡＢＳ共混合金的热性能、抗冲击强度介于纯ＰＶＣ和ＡＢＳ之间，而缺口冲击强度则优于ＰＶＣ和ＡＢＳ，且当ＡＢＳ含量为３０％时有最大值。这是由于ＰＶＣ／ＡＢＳ共混合金的微观结构造成的。ＰＶＣ／ＡＢＳ共混合金随着ＡＢＳ含量减少，橡胶粒子变小，当ＡＢＳ含量为３０％时，二组分相容性最好。     

Effects of composition and transesterification catalysts on the physico-chemical and dynamic properties of PC/PET blends rich in PC

Melt blending of polycarbonate (PC)/poly(ethylene terephthalate) (PET) rich in PC at absence/present of different type of tranesterification catalysts was carried out by using reactive extrusion method. The thermal, dynamic, and morphological properties were studied. It was found that all blends are formed by a PC matrix and a semicrystalline (12–20% of crystallinity) of PET dispersed phase. The addition of a catalyst in the mixing process promotes a refined and homogeneous dispersion of PET, as well as it enhances the dynamicmechanical behavior of PC/PET blends compared with PC. These effects are attributed to the emulsifying effect of the PC–PET copolymer generated by transesterification. Additionally, this copolymer contributes to the miscibility between phases as demonstrated by the glass transition (T _g) shift of PC phase and PET phase.