Morphology and Mechanical Properties of Thermoplastic Polyurethanes Containing Polyisobutylene/Poly(tetramethylene oxide) Mixed Segments

We investigated the thermal properties, microphase separated structure and mechanical properties of a series of thermoplastic polyurethanes (TPUs) containing both polyisobutylene (PIB) and poly(tetramethylene oxide) (PTMO) diols in the soft segment (SS). A series of TPUs were prepared with the same weight fraction of the SS but different ratio between PIB and PTMO diols. Molecular weight of the PTMO diol and chemical structure of the hard segment (HS) also varied. Dynamic mechanical analysis (DMA) measurements did not reveal strong microphase separation between PIB and PTMO in the SS. While it has been assumed that incorporating PTMO diol into the SS can enhance the phase mixing between the hard segment (HS) and SS, our results indicated that, in most cases, the degree of microphase separation of TPUs based on mixed diols is slightly higher than that of TPUs based on only PIB diol.     

纳米SiO2表面上的聚对苯二甲酸丁二醇酯预聚物接枝改性

纳米SiO2表面上的聚对苯二甲酸丁二醇酯预聚物接枝改性;纳米粒子; 表面改性;接枝; 聚对苯二甲酸丁二醇酯     

芳香族共聚酯液晶熔体流变学

较全面综述了热致液晶性芳香族共聚酯(TLCP)熔体流变学的最新研究成就，指出TLCP溶体具有许多特征流变行为，存在屈服应力、低粘虞、负第一法向应力差、孔口收缩、长松弛时间及它们显著的剪切速率(振动频率)、温度、时间和热历史的依赖性。     

TSDC and DSC Study of Effects of Physical Aging on Polybutylene Terephthalate (PBT)

The impact of the physical aging process on the electrical and thermal properties of semicrystalline polybutylene terephthalate (PBT) was investigated by means of thermally stimulated depolarization currents (TSDC) and differential scanning calorimetry (DSC). The TSDC technique was used to study the relaxation modes of PBT in the temperature range ?50° to + 120°C. The obtained spectra revealed two peaks located at temperature maxima of 45° and 93°C. The peak appearing at 45°C corresponds to the dielectric manifestation of the glass transition phenomenon (α-relaxation). The aim of this work is to study the effect of physical aging on this relaxation. The recording of TSDC peaks of aged PBT at different temperatures for different times revealed a reduction in their intensities and their shift towards higher temperatures when the aging becomes significant. This result can be explained by the diminution of molecular chain mobility, which is directly related to the area under the peak representing the polarization of the sample. This result was confirmed by DSC measurements, which revealed the growth and the shift of the peak, which is superimposed on the jump of the heat capacity, located around 38°C and characteristic of the glass transition, towards higher temperatures where aging becomes significant.     

热致液晶共聚酯的熔融行为及结晶结构研究

采用ＤＳＣ及ＷＡＸＤ手段对含对羟基苯甲酸热致液晶共聚酯的相变行为及结晶结构进行了初步研究。结果表明，聚合物中存在两种同属于正交晶系的不同堆积形态结晶结构，在相变上表现为双重熔融峰。     

液晶共聚物与PSF原位复合的界面研究

合成了两种热致性液晶共聚酯ＢＰ—ＬＣＰ和ＳＤＰ—ＬＣＰ，对其熔融指数、取向性作了考察。选用基体聚砜（ＰＳＦ）与液晶共聚酯进行熔融共混，得原位复合材料。ＳＥＭ断口形态显示了两种液晶在基体中不同的成纤性，并显示出两相的不相容性。采用ＦＴ—ＩＲ方法分析了液晶共聚酯与ＰＳＦ界面间的分子相互作用。进一步研究发现在ＰＳＦ／ＢＰ－ＬＣＰ原位复合体系中加入含ＰＳＦ和ＢＰ－ＬＣＰ的嵌段共聚物，其相容性得以改善     

Thermotropic Copolyesters. 1. Synthesis and Characterization of Liquid Crystal Copolyesters Containing the Bicyclo [2.2.2]octane Ring System

The syntheses and characterizations of poiy[oxy(2-chloro-l,4-phenylene)oxycarbonyl- l,4-bicyclo[2.2.2] octylenecarbonyl-co-oxy(2-chloro-l,4-phenylene)oxysebacoyl] and poly[oxy(2-methyl-l,4-phenylene)oxycarbonyl-l,4-bicyclo[2.2.2]octylenecarbonyl-co-oxy(2-methyl-l,4-phenylene)oxysebacoyl] are described. The resulting random copolyesters were characterized by infrared spectroscopy, proton magnetic resonance spectroscopy, solution viscosity, and differential scanning calorimetry. The random copolyesters formed birefringent fluid states in the melt.     

含异山梨醇的全生物基PBS嵌段共聚酯的制备及性能

采用熔融扩链法制备了高分子量的全生物基聚丁二酸丁二醇酯(PBS)-聚丁二酸异山梨醇酯嵌段共聚酯.GPC测试结果表明,该嵌段共聚酯在较高的异山梨醇(Is)含量时仍具有较高的分子量,其M_n介于3.5×10~4~7.0×10~4之间.采用TGA和DSC对嵌段共聚酯的热稳定性和结晶性能进行了研究,结果表明嵌段共聚酯保持了PBS优异的热稳定性和结晶性能,即使异山梨醇含量达60 mol%,其熔点较PBS仅下降2 K.采用DMA分析了嵌段共聚酯的玻璃化转变温度T_g,发现随着异山梨醇含量的增加,其T_g随之升高,当Is含量为60mol%时,嵌段共聚酯的T_g高达68℃,并且共聚酯的2个链段具有很好的相容性.力学性能测试结果表明,异山梨醇的引入可使PBS的力学性能得到明显地提高和调控,随着异山梨醇含量的增加,嵌段共聚酯的拉伸强度先增加后降低,断裂伸长率约是PBS的2倍,其中,当异山梨醇含量达60 mol%时,嵌段共聚酯的屈服强度由PBS的35.0 MPa增至43.0 MPa.     

Multiblock Copolymers Based on Highly Crystalline Polyethylene and Soft Poly(ethylene-co-butadiene) Segments: Towards Polyolefin Thermoplastic Elastomers

Block copolymers based on polyethylene (PE) and ethylene butadiene rubber (EBR) were obtained by successive controlled coordinative chain transfer polymerization (CCTP) of a mixture of ethylene and butadiene (80/20) and pure ethylene. EBR-b-PE diblock copolymers were synthesized using the {Me₂Si(C₁₃H₈)₂Nd(BH₄)₂Li(THF)}₂ complex in combination with n-butyl,n-octyl magnesium (BOMAG) used as both the alkylating and chain transfer agent (CTA). Triblock and multiblock copolymers featuring highly semi-crystalline PE hard segments and soft EBR segments were further obtained by the development of a bimetallic CTA, the pentanediyl-1,5-di(magnesium bromide) (PDMB). These new block copolymers undergo crystallization-driven organization into lamellar structures and exhibit a variety of mechanical properties, including excellent extensibility and elastic recovery in the case of triblock and multiblock copolymers.     

Synthesis and Characterization of Thermoplastic Polyurethaneureas based on Polyisobutylene and Poly(tetramethylene oxide) Segments

New thermoplastic polyurethaneureas (TPUU) based on polyisobutylene (PIB) and poly(tetramethylene oxide) (PTMO) segments have been synthesized possessing tensile properties comparable to conventional PTMO based TPUs. PIB based TPUU containing 35 weight (wt)% hard segment was synthesized by chain extension of H₂N-Allyl-PIB-Allyl-NH₂ with 4,4′ -methylene bis(phenylisocyanate) (MDI) and 1,4-butanediol (BDO) in toluene. The ultimate tensile strength (UTS) = 12 MPa and ultimate elongation = 70% were inferior to PTMO based polyurethane (UTS = 35 MPa, elongation at break = 600%). H₂N-Allyl-PIB-Allyl-NH₂ and HO-PTMO-OH in different proportions were chain extended in presence of MDI and BDO to obtain TPUUs containing 35 wt% hard segment. The polymers exhibited M _ns = 84000–138000 with polydispersity indices (PDIs) = 1.7–3.7. The UTS = 23–32 MPa and elongation at break = 250–675% was comparable to that of PTMO based polyurethane and significantly higher than the PIB based TPUU with the same Shore hardness. The Young's modulus of the polymers was strongly dependent and directly proportional to the PIB wt% in the SS of the TPUUs.     

含4，4＇－二羟基二苯酮热致液晶四元共聚酯的合成与表征

含４，４＇－二羟基二苯酮热致液晶四元共聚酯的合成与表征董德文，韩平，倪玉山，丁孟贤，韩伟（中国科学院长春应用化学研究所长春１３００２２）（吉林化工学院化工系吉林）关键词　热致液晶，共聚酯，向列型，二羟基二苯酮关于热致液晶芳香族聚酯的研究已有大量的报道...     

含X-型二维液晶基元和冠醚环的液晶共聚酯的研究

合成了一系列新的含X-型二维液晶基元和反式-4,4'-双(4-羟基苯基偶氮)二苯并-14-冠-4冠醚环的主链型液晶共聚酯. 通过GPC, [η], DSC, TG, WAXD和POM对其液晶性研究发现, 所有的共聚酯都呈现出向列相的丝状织构或纹影织构. 共聚酯的熔融温度(T_m)和各向同性温度(T_i)随共聚酯分子中反式-4,4'-双(4-羟基苯基偶氮)二苯并-14-冠-4用量的改变呈规律性变化.     

Self-assembly and Properties of Block Copolymers Containing Mesogen-Jacketed Liquid Crystalline Polymers as Rod Blocks

Mesogen-jacketed liquid crystalline polymer (MJLCP) has attracted great attention because of its rigid conformation, facile synthesis, and structural controllability. In this feature article, the self-assembly of MJLCP-based block copolymers (BCPs) is briefly reviewed, especially the nanostructures of rod-coil diblock copolymers (diBCPs), rod-rod diBCPs, and triblock copolymers. In addition, the properties of the self-assembled BCPs are also summarized, including their applications as liquid crystalline thermoplastic elastomers and solid polymer electrolytes. The article also discusses the major challenges and future directions in the study of MJLCP-based BCPs.     

Effect of Epoxy Resin on the Thermal,Mechanical and Rheological Properties of Polybutylene Terephthalate/Glycidyl Methacrylate Functionalized Methyl Methacrylate-butadiene Blend

Epoxy resin was used to modify polybutylene terephthalate(PBT) and glycidyl methacrylate functionalized methyl methacrylate-butadiene(MB-g-GMA) blend. Results show that MB-g-GMA dispersed in PBT matrix uniformly and PBT/MB-g-GMA/epoxy blends reveal good compatibility. However, the added epoxy resin restricted the mobility of PBT macromolecular chains during the growth process of the crystal, which reduced the final crystallinity of PBT. The PBT/MB-g-GMA blend containing 1%(mass fraction) epoxy resin exhibited good mechanical properties. For example, the notched impact strength of the PBT/MB-g-GMA blend with 1%(mass fraction) epoxy resin was about 2 times that of PBT/MB-g-GMA blend. Sanning electron microscope(SEM) results show that the shear yielding of the PBT matrix and the cavitations of rubber particles were the major toughening mechanisms. The chemical reaction between PBT and epoxy resin induced the high complex viscosity and storage modulus of PBT/MB-g-GMA blend.     

Liquid Crystalline Thiadiazole Derivatives: Thiadiazole Derivatives Containing Pyridine Ring as Terminal Group

The synthesis and mesomorphic behavior of a new series of liquid crystals containing 1, 3, 4‐thiadiazole and pyridine rings with ‐CH = N‐ central group are reported. All compounds exhibit enantiotropic smectic A mesophase, but the Schiff's base analogues have no mesomorphic behavior. The influence of the pyridine ring and thiadiazole ring is discussed.     

含聚醚链段聚酰亚胺膜的制备及气体分离性能

利用均苯四甲酸二酐（PMDA）与4,4’-二氨基二苯醚（ODA）和聚醚胺（PPO, Mn～2000）共聚合,合成聚酰胺酸前驱体,经热处理得到一系列含PPO链段的聚酰亚胺薄膜.研究了PPO链段的引入对薄膜结构及气体分离性能的影响.结果表明,在芳香族聚酰亚胺中引入柔性链段PPO有利于气体分子的传输.得益于PPO链段在分离膜内部形成的微相分离结构,气体分子在分离膜内的扩散系数随PPO含量的增加显著提升.当PPO含量为65 wt%时,PPO链段在分离膜内仍呈现非晶相,CO₂渗透系数高达131.61 Barrer,比PMDA/ODA均聚聚酰亚胺薄膜提高22倍.同时,得益于聚醚链段对CO₂独特的亲和作用,随着PPO含量的提高,分离膜对CO₂/N₂的分离系数由18.77提高至30.12.结果表明PPO链段的引入对于调控聚酰亚胺膜的结构和气体分离性能具有重要作用.     

含硫醚链节的透明聚酰胺酸的合成及表征

合成了一种具有耐高温、氧化稳定性及透明性的聚硫醚酰胺酸，并对各步中间产物进行了基本表征。讨论了温度对硫醚二酐形成的影响。     

主链含PEO链段的聚对苯乙炔类蓝色电致发光共聚物

采用Ｗｉｔｔｉｇ反应合成了一种分子主链上烷氧基取代刚性共轭聚对苯乙炔（ＰＰＶ）民柔性聚氧化乙烯（ＰＥＯ）链段交替排列的、可溶于氯仿与四氢呋喃等普通有机溶剂的新型结构的聚对苯乙炔类功能性发光共聚物ＥＯ－ＰＰＶ。采用ＦＴ－ＩＲ、＾１Ｈ－ＮＭＲ、ＤＳＣ、ＧＰＣ、元素分析等手段对共聚物进行了表征,并制备了结构为（Ａｌ）Ｃａ／ＥＯ－ＰＰＶ／ＩＴＯ的单层电致发光器件、器件的最大发光波长位于４７５ｎｍ（蓝光）。