聚亚苯基苯并二噻唑与聚亚苯基苯产二E唑的热分解

用高分辨裂解气相色谱－质谱（HR PyGC-MS)研究了聚亚苯基苯并二噻唑、聚亚苯基苯并二E唑的热分解行为，鉴定了相应裂解产物的组成、分布及其与高分子结构的关系，并用热重法（TG）测定了它们热分解反应动力学参数，提出了其热分解反应机理。     

聚亚苯基苯并二噁唑缩聚反应动力学

以4,6-二氨基间苯二酚磷酸盐(DAR.2HP3O4)和对苯二甲酸(TA)为原料经非均相逐步缩聚反应制得聚亚苯基苯并二噁唑(PBO)。该反应可分为溶解控制(齐聚合)、反应动力学控制(预聚合)以及高分子链段扩散控制(后聚合)3个阶段。探讨了各阶段的反应过程,并对PBO预聚合反应动力学进行了研究。结果表明:其动力学符合不可逆二级反应机理,反应活化能为51.9 kJ/mol。     

聚亚苯基苯并二噻唑纤维力学性能影响因素的研究

研究了聚亚苯基苯并二噻唑分子量，纺丝工艺，热处理温度，时间，负荷等工艺条件对纤维力学性能的影响。结果表明分子量３０，０００左右的ＰＢＺＴ纤维经５００－５５０℃、负荷４１０ＭＰａ、热处理１２ｓ，得到的纤维力学性能最优。纤维的直径越细，越均匀，力学性能越好。     

苯并二噁唑系列聚合物的合成及表征

以4,6-二氨基-1,3-苯二酚盐酸盐为原料,分别和对苯二甲酸、1,4-萘二甲酸、2,6-萘二甲酸、2,5-噻吩二甲酸、4,4-′(1,2-二苯基乙烯)二甲酸在多聚磷酸介质中反应,合成单环的聚(1,4-亚苯基)苯并二噁唑(PBO)、稠环的聚(1,4-亚萘基)苯并二噁唑(1,4-PNBO)和聚(2,6-亚萘基)苯并二噁唑(2,6-PNBO)、杂环的聚(2,5-亚噻吩基)苯并二噁唑(PTBO)及含有两个苯环的聚-4,4′-亚(1,2-二苯乙烯基)苯并二噁唑(4,4′-PDPEBO).采用傅立叶红外光谱、热重分析、元素分析、特性黏数分析对系列聚合物进行了表征.研究结果表明PBO、1,4-PNBO、4,4-′PDPEBO、2,6-PNBO和PTBO 5种聚合物的耐热性能依次降低,特性黏数依次为25.40、16.76、20.63、15.38和14.63 dL/g.     

聚亚苯基苯并二噻唑的X射线衍射研究

本文用X射线衍射研究了聚亚苯基苯并二噻唑(PBT)薄膜的结构特征。衍射结果表明PBT在液晶态成膜具有高的取向度,分子链在垂直于取向方向呈有序的二维周期排列,沿取向方向分子链相互间无序平行排列。热处理可明显提高PBT的有序度,即在垂直于取向方向分子链的二维排列更规整,晶格畸变减小,而取向方向分子链中苯杂环呈群集排列,出现三维有序的衍射斑点,测其群集结构平面的法线与取向方向夹角为29°。     

含亚甲基链段苯并二嗯唑类聚合物的合成、表征及性能

通过溶液缩聚的方法合成了一系列含有不同长度亚甲基链段的聚苯并羟基酰胺（PHACx），然后在200～300℃下环化脱水制备了相应的聚多亚甲基苯并二嘿唑（PBOCx），并对其结构进行了表征，探讨了聚合物的溶解性、热性能和光物理性能。研究表明：在主链上引入亚甲基提高了苯并二嘿唑类聚合物在有机溶剂中的溶解性，其中PBOC3和PBOC4具有较好的溶解性能，但随着亚甲基数量的进一步增加，溶解性有下降趋势。此外，所有的PBOCx聚合物均表现出良好的耐热性，在空气中的热分解温度可达到450℃以上。对聚合物光物理性能的初步研究表明：随着柔性链段的增加，电子共轭作用逐渐减弱，紫外吸收发生了蓝移。     

聚对-亚苯基苯并二噻唑的导电性能

聚对-亚苯基苯并二噻唑(PBZT)的取向薄膜是由苯环及苯杂环组成的直棒状刚性大分子组成.分子链上的非定域π电子是其具有导电性能的基本条件.经交流复阻抗谱法测得PBZT簿膜在取向方向的电导率σ_∥为10~(-6)s·cm~(-1),在簿膜厚度方向的电导率σ_⊥为10~(-10)s·cm~(-1).PBZT取向簿膜电导率具有很大的各向异性,σ∥/σ⊥=10~4.在460℃以上热处理,PBZT分子的共轭结构可进一步改善,共轭链长增加了,可使电导率提高一个数量级.     

聚苯基不对称三嗪的热分解

用高分辨裂解气相色谱－质谱（ＨＲＰｙＧＣ－ＭＳ）考察了由对苯二眯腙和四种不同芳香族四酮合成的聚苯基不对称三嗪的热分解行为，鉴定了相应裂解产物的组成、分布及其与高分子结构的关系，并用热重法（ＴＧ）测定了它们的热分解反应动力学参数，提出了其热分解反应机理．     

含亚甲基链段苯并二(口恶)唑类聚合物的合成、表征及性能

通过溶液缩聚的方法合成了一系列含有不同长度亚甲基链段的聚苯并羟基酰胺(PHACx),然后在200～300 ℃下环化脱水制备了相应的聚多亚甲基苯并二唑(PBOCx),并对其结构进行了表征,探讨了聚合物的溶解性、热性能和光物理性能.研究表明:在主链上引入亚甲基提高了苯并二唑类聚合物在有机溶剂中的溶解性,其中PBOC3 和PBOC4具有较好的溶解性能,但随着亚甲基数量的进一步增加,溶解性有下降趋势.此外,所有的PBOCx聚合物均表现出良好的耐热性,在空气中的热分解温度可达到450 ℃以上.对聚合物光物理性能的初步研究表明:随着柔性链段的增加,电子共轭作用逐渐减弱,紫外吸收发生了蓝移.     

聚对二亚甲基苯的激光离解质谱分析

聚对二亚甲基苯的激光离解质谱分析高文德，刘维铬，王守文，马洪，敖十庆，邓万卉，许建光（四川联合大学成都６１００６４）崔保顺，唐永建，马宏伟（中国工程物理研究院成都６１０００３）关键词激光，质谱，聚对二亚甲基苯聚对二亚甲基苯难溶于有机溶剂且加热时立即分...     

聚β-羟基丁酸酯和聚ε-己内酯的酯交换反应

以辛酸亚锡为催化剂 ,研究了聚 β 羟基丁酸酯 (PHB)与聚ε 己内酯 (PCL)在液相条件下的酯交换反应 .讨论了反应时间 ,反应温度和催化剂浓度对酯交换反应的影响 .采用1 3C NMR ,FTIR ,DSC ,WAXD和TGA等方法对PHB和PCL共聚酯 (PHB co PCL)的结构进行了表征 ,并对其结晶行为、晶体结构和热稳定性进行了研究 .结果表明 ,通过酯交换反应 ,所得到的共聚酯为嵌段共聚物 .提高反应温度和延长反应时间有利于酯交换反应的发生 .随着酯交换量的增加 ,PHB co PCL的结晶行为发生很大的变化 .但是 ,PHB co PCL晶体结构并没有因为PCL链段的引入而发生变化 ,而且它的热稳定性在空气气氛中略有提高     

The Thermal Degradation Mechanism and Thermal Mechanical Properties of Two High Performance Heterocyclic Polymer Fibers

The thermal mechanical properties and degradation behaviors were studied on fibers prepared from two high-performance, heterocyclic polymers, poly(p-phenylenebenzobisthiazole) (PBZT) and poly(p-phenylenebenzobisoxazole) (PBZO). Our research demonstrated that these two fibers exhibited excellent mechanical properties and outstanding thermal and thermo-oxidative stability. Their long-term mechanical tensile performance at high temperatures was found to be critically associated with the stability of the C—O or C—S linkage at the heterocyclic rings on these polymers' backbones. PBZO fibers with the C—O linkages displayed substantially higher thermal stability compared to PBZT containing C—S linkages. High resolution pyrolysis-gas chromatography/mass spectrometry provided the information of the pyrolyzates' compositions and distributions as well as their relationships with the structures of PBZT and PBZO. Based on the analysis of the compositions and distributions of all pyrolyzates at different temperatures, it was found that the thermal degradation mechanisms for both of these heterocyclic polymers were identical. Kevlar®-49 fibers were also studied under the same experimental conditions in order to make a comparison of thermo-oxidative stability and long-term mechanical performance at high temperatures with PBZO and PBZT fibers. The data of two high-performance aromatic polyimide fibers were also included as references.This revised version was published online in November 2005 with corrections to the Cover Date.     

Synthesis and characterization of saturated and unsaturated polysulfide polymers and their thermal degradation processes investigated by flash pyrolysis–gas chromatography/mass spectrometry

The synthesis of polysulfide polymers with unsaturated and saturated units in the backbone and their characterization by Fourier transform infrared, NMR, gel permeation chromatography, thermogravimetric analysis, and differential scanning calorimetry are reported. This is the first report on an analysis of the thermal degradation of an unsaturated polysulfide polymer [poly(2‐butene sulfide)] carried out by pyrolysis–gas chromatography/mass spectrometry (Py–GC/MS). A unique phenomenon of exothermic degradation has been detected by differential thermal analysis and has been attributed to the energetics of the unsaturated polysulfide linkage during degradation. The thermal degradation products studied by Py–GC/MS indicate that the formation of sulfur‐containing products is more favored than the formation of non‐sulfur‐containing products. Furthermore, a comparative study of the thermal degradation of unsaturated and saturated polysulfide polymers has been conducted with thermogravimetry and Py–GC/MS analyses. These analyses have shown that the mechanisms of degradation of these polymers are different, and the lower number of pyrolysis products indicates a selective cleavage of the polymer during degradation in the saturated polysulfide polymers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 638–649, 2005     

Photochemical degradation study of polyvinyl acetate paints used in artworks by Py–GC/MS

Photochemical degradation of commercial polyvinyl acetate (PVAc) homopolymer and PVAc paints mixed with burnt umber, cobalt blue, cadmium red dark, nickel azo yellow and titanium white commonly used for artworks were studied by pyrolysis–gas chromatography/mass spectrometry (Py–GC/MS) and Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR). Py–GC/MS with single-shot technique was used for the characterization of the thermal degradation of PVAc at different temperatures, while the double-shot technique of Py–GC/MS was used to reveal the differences in the specimens before and after UV ageing, including the changes of detectable amounts of deacetylation product – acetic acid and plasticizers such as diethyl phthalate (DEP). Furthermore, the relative concentration of the pyrolysis products of the paint samples could be measured and compared in the second step of the double-shot Py–GC/MS, which are highly dependent on the presence of pigments and the ageing status of PVAc paints.     

聚对二氧环己酮-乙交酯缝合线体外降解研究

用DSC和X ray衍射法对聚对二氧环己酮 乙交酯 (PDG)缝合线的初期体外降解过程进行了研究 ,并使用纤维摄影仪对纤维在降解过程中的表面形态变化进行了观察 .研究结果表明 ,在本工艺条件下得到的PDG缝合线在体外降解过程中分为三个阶段降解 ,即无定形区降解、原纤间非晶区降解和晶区水解 .在体外降解过程中 ,PDS缝合线以横向断裂为主 ,而PDG则通过表面积的大块脱落来完成降解过程     

Thermal stability and degradation of poly(N-(4-chlorophenyl) acrylamide) homopolymer and copolymer of N-(4-chlorophenyl) acrylamide with methyl methacrylate

Different concentrations of copolymer of (N-(4-chlorophenyl) acrylamide) (CA) with methyl methacrylate (MMA) were prepared and the reactivity ratio values of copolymerization were calculated using ¹H NMR technique. Thermal analysis of the copolymers showed that the thermal stability is intermediate between poly(N-(4-chlorophenyl) acrylamide) (PCA) and poly(methyl methacrylate) (PMMA) homopolymers. Thermal degradation products of the PCA were identified by GC–MS techniques. It seems that the mechanism of degradation of PCA homopolymer is characterized by free radical formation followed by recombination along the backbone chain. The activation energies of the thermal degradation of the copolymers were calculated using Arrhenius relationship.     

含间苯基聚醚酮醚酮酮的合成和性能研究

自英国ＩＣＩ公司开发聚醚醚酮（ＰＥＥＫ）并于八十年代初期商品化以来［１］,聚芳醚酮作为一类新型结构的高性能特种工程塑料得到了惊人的发展,不同结构的聚芳醚酮相继出现．Ｊａｎｓｏｎ［２］等以对苯二甲酰氯（ＴＰＣ）和４,４′ 二苯氧基二苯酮（ＤＰＢＰ）为单...     

含聚1,3-二氧戊环链段可降解pH敏感性水凝胶的合成与表征

制备了含聚 1,3 二氧戊环链段具有pH敏感性的可解体聚合物凝胶网络 ,网络可在水中及有机溶剂中溶胀 ,且由聚 1,3 二氧戊环构成的水凝胶成分可以在酸性介质中降解 ,使网络解体 .利用红外光谱、色 质联谱等分析手段对聚合物凝胶网络进行了表征 .通过对降解产物的分析 ,一方面证实了降解现象的存在 ,另一方面证实了聚合反应机理     

聚对二氧环己酮/聚乙二醇多嵌段共聚物的合成与表征

首先合成双端羟基的聚对二氧环己酮预聚物(PPDO)和双端羧基的聚乙二醇预聚物(PEG),然后以丁二酸酐/二环己基碳二亚胺(DCC)将PPDO与PEG偶联共聚,得到PPDO/PEG多嵌段共聚物.通过1H-NMR和GPC表征了聚合物的结构和分子量.采用差示扫描量热法(DSC)和热重分析(TGA)研究了共聚物的结晶性能和热稳定性.用透析法制备了共聚物纳米粒子,并用动态光散射(DLS)表征了共聚物纳米粒子的粒径及分散度,结果表明,随着共聚物亲水链段PEG含量的增加,其纳米粒子更易形成,粒子粒径随共聚物分子量增大而增大.     

Thermal degradation of poly(vinylpyridine)s

The thermal stability and the temperature at which maximum degradation yields are detected were quite similar for both poly(2-vinylpyridine) (P2VP) and poly(4-vinylpyridine) (P4VP). However, considerable differences among the thermal degradation products of both polymers were detected indicating a correlation between the polymer structure and the degradation mechanism. Direct pyrolysis mass spectrometry analyses revealed that P2VP degrades via a complex degradation mechanism, yielding mainly pyridine, monomer, and protonated oligomers, whereas depolymerization of P4VP takes place in accordance with the general thermal behaviour of vinyl polymers. The complex thermal degradation behaviour for P2VP is associated with the position of the nitrogen atom in the pyridine ring, with σ-effect.