聚环氧乙烷/脂肪族聚碳酸酯共混研究

本文用差热分析(DSC)和红外光谱仪(FTIR)研究了聚环氧乙烷(PEO)和新型聚合物脂肪族聚碳酸酯(PPC)共混热行为和大分子间相互作用。熔点下降方法给出 PEO/PPC 混合体系在320K 下相互作用参数为-0.46,FTIR 谱表明 PPC 大分子链和 PEO 大分子链存在较强的相互作用;PEO/PPC 共混形态随 PPC 含量增加发生了较大变化.     

聚环氧乙烷(PEO)与聚醋酸乙烯酯(PVA)的共混研究

动态力学谱研究表明熔融共混PVA/PEO体系的无定形态中存在着纯PEO及PVA/PEO的相容或部分相容相。相容或部分相容相的T_g随共混物组成的变化远高于按照FOX方程的计算值。用结晶和分子间相互作用解释了这种对FOX方程的偏离。应用FTIR差示光谱技术对PVA/PEO共混物和PVA/DGDE浓溶液的研究证实了PVA分子链上酯基和PEO分子链存在着强的相互作用。     

固体NMR研究PAA/PEO共混物中氢键相互作用与结构演化

分子间相互作用是决定材料结构和性能的关键因素之一,而如何在分子水上实现对复杂相互作用分子的检测仍然是一个挑战性课题。本工作首先在不同p H值条下以聚丙烯酸/聚环氧乙烷(PAA/PEO)的混合水溶液制备了系列的固体薄膜,然后采用多种基于连续相调制多脉冲技术的一维和二维~1H多脉冲去耦(CRAMPS)固体NMR新技术,并结合高分辨~(13)C交叉极化魔角旋转(CPMAS)、~(23)Na多量子(MQ)等多核固体NMR实验,对PAA/PEO聚合物共混物的微观结构和动力学进行了原位和系统的研究。通过不同类型的~1H高分辨CRAMPS实验检测到共混物中包含多种不同类型质子:通过氢键相互作用形成二聚体的COOH基团、自由COOH基团、与水结合的COOH基团和主链基团。随着p H值的升高,除主链质子外,大部分其它区域的信号都明显降低,这是由于PAA与PEO以及水的氢键作用减弱所致。这些CRAMPS NMR技术也被用来阐明不同p H值制备的样品中不同基团的分子运动性。此外,二维~1H-~1H自旋交换NMR实验提供了关于聚合物PAA与PEO大分子链间、以及水与聚合物的相互作用。~1H自旋扩散实验表明,在这些共混物中明显存在相微观相分离的结构,并且测定的分散相区尺寸约为17 nm。~(23)Na MQMAS实验揭示了在共混物中存在两种类型~(23)Na位,一种是自由的钠离子,另一种是与大分子相互作用的Na离子。特别是通过~1H-检测的~(23)Na-~1H CPMAS实验揭示了Na~+离子的位置远离PEO而与PAA临近。上述这些SSNMR实验结果在分子水平上提供了氢键相互作用对PAA/PEO共混物微观结构和动力学影响的详细信息,可以获得不同p H值对PAA与PEO的氢键作用、相容性、微观结构、水-聚合物相互作用和不同组分分子运动性的影响。在上述核磁共振研究的基础上,我们提出了一种新的PAA/PEO共混物的结构模型,该模型首次成功地揭示了不同的p H值对PAA/PEO共混物中微观结构和动力学的影响。本工作清楚地表明,固态核磁共振是在分子水平上研究具有复杂相互作用的多相聚合物材料的有力工具。本文的研究工作对于探索检测聚合物弱相互作用的新方法和发展基于氢键相互作用的聚合物新材料的开发具有重要意义。     

聚碳酸亚丙酯对聚(β-羟基丁酸酯-β-羟基戊酸酯)结晶行为的影响

用FTIR和DSC研究了PHBV及其与聚碳酸亚丙酯(PPC)熔融共混样的熔融结晶行为和等温结晶动力学.结果表明,PHBV与PPC熔融共混过程中发生了酯交换反应,两组分间存在一定的相互作用.PPC虽然能降低PHBV结晶折迭链的表面自由能,但同时也能够降低PHBV的结晶度、球晶径向生长速率、平衡熔点和结晶能力.     

聚甲基丙烯酸甲酯与聚醋酸乙烯酯共混的红外光谱研究

用红外光谱(FTIR)研究了聚甲基丙烯酸甲酯(PMMA)与聚醋酸乙烯酯(PVAc)共混体系相容性,在160℃以上共混体系发生相分离;分相体系与非分相体系的FTIR谱明显不同;共混体系的FTIR谱不能从两统组分红外光谱简单加和得到;结果表明大分子构象发生了变化,PMMA/PVAc体系相容可能是大分子构象熵变所致。     

结晶-非晶共混体系的结晶行为研究——PEO/PMMA与PEO/PVA共混物

用DSC和傅里叶红外(FTIR)光谱表征PEO/PMMA和PEO/PVA共混体系的结晶行为。发现PEO/PVA体系的结晶度与其组成的变化是一致的;而PEO/PMMA体系的结晶度随非晶组分增加而下降的速度,从与组成变化一致到比后者快,但又随时间而改变。对此结晶/非晶共混体系的结晶度随组成和时间而变化的现象,可用体系的玻璃化转变温度(T_g)来解释。     

高氯酸锂对PEO结晶结构和结晶行为的影响

利用配备热台的偏光显微镜(POM)、红外光谱仪(FTIR)和示差扫描量热器(DSC)等实验方法研究了高氯酸锂(LiClO4)与聚氧化乙烯(PEO)之间的络合作用对PEO结晶行为和结晶形态的影响.DSC测试结果表明在LiClO4/PEO二元共混体系中,PEO的熔融温度、结晶温度随着锂盐含量的增加出现先增加后降低的现象;而结晶度则是先不变后降低.FTIR结果表明LiClO4影响聚合物结晶性能的原因是Li+能和PEO中的醚基的络合作用.POM观察结果发现LiClO4/PEO共混体系中存在聚合物的球晶,共混体系中聚合物的球晶生长速率都随着结晶温度的升高而下降,并且球晶生长速率还随着体系中随LiClO4含量的增加而减小.     

基于Li6.4La3Zr1.4Ta0.6O12/聚合物复合固态电解质的制备及电化学性能

采用溶液浇注法制备以Li_(6.4)La_3Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)为填料、聚氧化乙烯(PEO)与聚碳酸亚丙酯(PPC)共混的固态复合电解质膜,探讨了LLZTO含量和PPC/PEO比例对复合固态电解质离子电导率的影响。研究发现,当LLZTO含量为30%(w/w)及PPC/PEO质量比为1∶1时,固态复合电解质室温离子电导率最高,达到1.14×10~(-4)S·cm~(-1)。LLZTO和PPC的加入,降低了PEO基电解质的结晶性,提高了离子电导率、电化学稳定窗口(4.7 V)和锂离子迁移数(0.25),并改善了电解质与金属锂的化学稳定性。该固态复合电解质与LiFePO_4/Li组装固态锂电池,室温下在0.1C循环70次后容量保持率82%,60℃下0.1C循环100次后容量保持率79%,0.5C和1C倍率下放电比容量仍能达到120.7和112.6 mAh·g~(-1)。     

聚环氧乙烷(PE0)与聚双酚A羟基醚(PBHE)共混体系的研究

 用偏光显微镜(PLM)、扭辫(TBA)、IR及WAXD对PEO/PBHE共混体系结晶形态进行了研究。结果表明,PEO含量在50％以上的共混体系,几乎完全被PEO球晶充满,非晶态PBHE作为微区分散在大球晶之间或球晶之中。PEO含量为40％和30％的照片上呈现树枝晶。PEO含量为20％以下时照片中不再看到结晶出现,PEO与PBHE形成单一非晶相。PEO/PBHE共混体系的组分之间存在着氢键相互作用,这种作用强于PBHE分子间的氢键作用。共混体系的结晶度及T_g随PBHE组分含量的增加,前者减小后者增加并符合FOX方程揭示的规律。PEO与PBHE具有很好的相容性。     

聚乳酸/聚苯乙烯共混物的热氧稳定性研究

通过溶液浇铸法制备了聚乳酸/聚苯乙烯共混物,以差热-热重分析研究了共混物的热氧稳定性,结果表明聚乳酸中引入聚苯乙烯,可以增强聚乳酸/聚苯乙烯共混物的热氧稳定性.采用红外光谱分析了共混物不同结构的分子链间相互作用,证实聚乳酸大分子链羰基的未共用电子对和聚苯乙烯大分子链侧基苯环的π电子形成了n-π键.     

Effect of crosslinking on intermolecular interactions in thermosetting blends of epoxy resin with poly(ethylene oxide)

The miscibility and intermolecular-specific interactions in thermosetting blends of epoxy resin (ER) with poly(ethylene oxide) (PEO) cured with various amounts of 1,3,5-tridroxybenzene (THB) were investigated by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The glass-transition behavior indicated that all the blends were miscible and had homogeneous amorphous phases; FTIR showed that there were the intermolecular hydrogen-bonding interactions between crosslinked ER and PEO. However, both the glass-transition behavior and infrared spectroscopy also indicated that the intermolecular interactions were significantly reduced by the formation of crosslinked structures, which was shown by comparing the experimental results of poly(hydroxyether of bisphenol A) (PH)/PEO and ER/PEO blends cured with various amounts of the curing agent. In ER/PEO blends the intermolecular hydrogen-bonding interactions were much weaker than the self-association of hydroxyls of ER, which was in marked contrast to the interactions in PH/PEO blends. In ER/PEO blends with various amounts of the curing agent, the intermolecular interactions between epoxy polymers and PEO were reduced with an increasing degree of crosslinking. The results were interpreted in terms of the effect of crosslinking on the intermolecular interactions, such as steric shielding, the screening effect, and chain connectivity resulting from the formation of the three-dimensional crosslinked network, which could reduce the intermolecular hydrogen-bonding interactions among hydroxyls of ER versus ether oxygen atoms of PEO. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2567–2575, 2004     

Synthesis and characterization of a vinyl‐terminated benzoxazine monomer and its blends with poly(ethylene oxide)

A vinyl‐terminated benzoxazine (VB‐a), which could be polymerized through ring‐opening polymerization, was synthesized through the Mannich condensation of bisphenol A, formaldehyde, and allylamine. This VB‐a monomer was then subjected to blending with poly(ethylene oxide) (PEO), followed by thermal curing, to form poly(VB‐a)/PEO blends. The specific interactions, miscibility, morphology, and thermal properties of these blends were investigated with Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry, dynamic mechanical analysis (DMA), and scanning electron microscopy (SEM). Before curing, we found that PEO was miscible with VB‐a, as evidenced by the existence of a single composition‐dependent glass transition temperature (T_g) for each composition. The FTIR spectra revealed the presence of hydrogen‐bonding interactions between the hydroxyl groups of poly(VB‐a) and the ether groups of PEO. Indeed, the ring‐opening reaction and subsequent polymerization of the benzoxazine were facilitated significantly by the presence of PEO. After curing, DMA results indicated that the 50/50 poly(VB‐a)/PEO blend exhibited two values of T_g: one broad peak appeared in the lower temperature region, whereas the other (at ca. 327 °C, in the higher temperature region) was higher than that of pristine poly(VB‐a) (301 °C). The presence of two glass transitions in the blend suggested that this blend system was only partially miscible. Moreover, SEM micrographs indicated that the poly(VB‐a)/PEO blends were heterogeneous. The volume fraction of PEO in the blends had a strong effect on the morphology. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 644–653, 2007     

Poly(hydroxyether of phenolphthalein) and its blends with poly(ethylene oxide)

Poly(hydroxyether of phenolphthalein) (PPH) was synthesized through the polycondensation of phenolphthalein with epichlorohydrin. It was characterized by Fourier transform infrared (FTIR) spectroscopy, NMR spectroscopy, and differential scanning calorimetry (DSC). The miscibility of the blends of PPH with poly(ethylene oxide) (PEO) was established on the basis of the thermal analysis results. DSC showed that the PPH/PEO blends prepared via casting from N,N‐dimethylformamide possessed single, composition‐dependent glass‐transition temperatures. Therefore, the blends were miscible in the amorphous state for all compositions. FTIR studies indicated that there were competitive hydrogen‐bonding interactions with the addition of PEO to the system, which were involved with OH…O?C〈, ? OH…? OH, and ? OH vs ether oxygen atoms of PEO hydrogen bonding, that is both intramolecular and intermolecular, between PPH and PEO). Some of the hydroxyl stretching vibration bands significantly shifted to higher frequencies, whereas others shifted to lower frequencies, and this suggested the formation of hydrogen bonds between the pendant hydroxyls of PPH and ether oxygen atoms of PEO, which were stronger than the intramolecular hydrogen bonding between hydroxyls and carbonyls of PPH. The FTIR spectra in the range of carbonyl stretching vibrations showed that the hydroxyl‐associated carbonyl groups were partially set free because of the presence of the competitive hydrogen‐bonding interactions. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 466–475, 2003     

Thermosetting polymer blends of unsaturated polyester resin and poly(ethylene oxide). I. Miscibility and thermal properties

The miscibility and thermal properties of polyethylene oxide(PEO)/oligoester resin (OER) blends and PEO/crosslinked polyester (PER) blends were studied by differential scanning calorimetry (DSC). The effect of quenching process on the crystallization behavior of PEO for these two systems were investigated and discussed in details. It has been found that a single, composition dependent glass transition temperature (T_g) was observed for all the blends, indicating that the two systems are miscible in the amorphous state at overall compositions. From the melting point depression of PEO, the interaction parameter χ₁₂ for PEO/OER blends and that for PEO/PER blends were found to be −1.29 and −2.01, respectively. The negative values of χ₁₂ confirmed that both PEO/OER blends and PEO/PER blends are miscible in the molten state. Quenching process has a greater hindrance on the crystallization of PEO/OER blends than on that of PEO/PER blends. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 3161–3168, 1997     

氨酯化合物对聚碳酸1,2-丙二酯的同时增韧和增强研究

采用非异氰酸酯路线合成了1,6-六亚甲基二氨基甲酸羟异丙酯(BPU),分子量为320.利用熔融共混方法制备了聚碳酸1,2-丙二酯(PPC)/BPU共混物.研究发现BPU与PPC间有较好的相容性,随着BPU含量的增加,共混体系的起始热分解温度(Td.5％)可分别增加24～33℃,共混物韧性也显著提高,断裂伸长率最大可增至...     

聚β-羟基丁酸酯/超高分子量聚氧化乙烯共混体系相容性和结晶行为

为了解决废弃塑料引起的“白色污染”问题,世界各国竞相研制开发可生物降解高分子材料,其中,有关聚β 羟基丁酸酯［ｐｏｌｙ（β ｈｙｄｒｏｘｙｂｕｔｙｒａｔｅ）（ＰＨＢ）］的研究尤其活跃．然而,由于商品价格较高,材料本身抗冲击性能较差、加工窗口较窄等限制...     

PLA,PPC和PHBV共混物的热性能、力学性能和生物降解性能研究

将聚乳酸(PLA)、聚碳酸酯(PPC)及β-羟基丁酸酯与β-羟基戊酸酯共聚物(PHBV)以溶液浇注法制备了各种不同比例的共混膜(60/20/20,40/20/40,40/40/20,20/60/20,20/40/40,20/20/60)。采用示差扫描量热分析(DSC)和热重分析(TG)研究了共混物的热性能,采用万能材料试验机研究了共混物的力学性能,通过土壤悬浊拟环境降解实验和扫描电子显微镜(SEM)研究了共混材料的环境生物降解性能。结果显示,该三元共混体系是部分相容的体系,PLA增加了材料的强度,PPC增加了材料的断裂伸长,PHBV则提高了材料的环境生物降解速率,三者优势互补,是一种有应用前景的生物降解共混体系。     

Ternary blends of poly(ethylene oxide) and acrylate-based copolymers: Crystallinity, miscibility, interactions and proton conductivity

In the present work, blends of poly(ethylene oxide) (PEO), poly(acrylonitrile-co-methyl acrylate) (PANMA) and poly(4-vinylphenol-co-2-hydroxyethyl methacrylate) (PVPh-HEM) were studied by DSC, FTIR and electrochemical impedance spectroscopy (EIS). PEO/PANMA blends were found to be immiscible, while PEO/PVPh-HEM blends are miscible and PVPh-HEM/PANMA exhibits partial miscibility behaviour. The ternary PEO/PANMA/PVPh-HEM blends exhibited miscible compositions for PVPh-HEM and PEO-rich systems. The miscibility observed is a direct consequence of the hydrogen bond interactions among the polymer chains, in which the phenol groups in PVPh-HEM interact with both PEO and PANMA chains. The proton conductivity of a selected membrane based on the ternary blend containing 60% PEO and doped with H₃PO₄ aqueous solution reached 8 × 10⁻³ Ω⁻¹ cm⁻¹ at room temperature and 3 × 10⁻² Ω⁻¹ cm⁻¹ at 80 °C.     

聚β—羟基丁酯酯／超高分子量聚氧化乙烯共混体系相容性和结晶行为

为了解决废弃塑料引起的“白色污染”问题,世界各国竞相研制开发可生物降解高分子材料,其中,有关聚β羟基丁酸酯［ｐｏｌｙ（βｈｙｄｒｏｘｙｂｕｔｙｒａｔｅ）（ＰＨＢ）］的研究尤其活跃．然而,由于商品价格较高,材料本身抗冲击性能较差、加工窗口较窄等限制...