Preparation of Polylactide/Poly(ether)urethane Blends with Excellent Electro-actuated Shape Memory <Emphasis Type="Italic">via</Emphasis> Incorporating Carbon Black and Carbon Nanotubes Hybrids Fillers

In this work, hybrid conductive fillers of carbon black (CB) and carbon nanotubes (CNTs) were introduced into polylactide (PLA)/thermoplastic poly(ether)urethane (TPU) blend (70/30 by weight) to tune the phase morphology and realize rapid electrically actuated shape memory effect (SME). Particularly, the dispersion of conductive fillers, the phase morphology, the electrical conductivities and the shape memory properties of the composites containing CB or CB/CNTs were comparatively investigated. The results suggested that both CB and CNTs were selectively localized in TPU phase, and induced the morphological change from the sea-island structure to the co-continuous structure. The presence of CNTs resulted in a denser CB/CNTs network, which enhanced the continuity of TPU phase. Because the formed continuous TPU phase provided stronger recovery driving force, the PLA/TPU/CB/CNTs composites showed better shape recovery properties compared with the PLA/TPU/CB composites at the same CB content. Moreover, the CB and CNTs exerted a synergistic effect on enhancing the electrical conductivities of the composites. As a result, the prepared composites exhibited excellent electrically actuated SME and the shape recovery speed was also greatly enhanced. This work demonstrated a promising strategy to achieve rapid electrically actuated SME via the addition of hybrid nanoparticles with self-networking ability in binary PLA/TPU blends over a much larger composition range.     

碳纳米管的加入对聚偏氟乙烯/丙烯酸酯共混物形状记忆性能的影响

利用聚偏氟乙烯(PVDF)微小结晶的物理交联点作用,制备了形状记忆性能优异的聚偏氟乙烯/丙烯酸酯聚合物(PVDF/ACM)共混材料。为提高其形状回复应力,又将碳纳米管(CNT)引入该共混体系中,系统研究了PVDF/ACM/CNT三元体系纳米复合材料的制备、结构及性能。结果表明,碳纳米管在PVDF/ACM体系中分散均匀;在基本保持其形状记忆性能的前提下,加入质量分数为4%的CNT,材料在25℃时的储能模量由2000 MPa提高至3130 MPa。     

Modification of Polylactide Nonwovens with Carbon Nanotubes and Ladder Poly(silsesquioxane)

Electrospun nonwovens of poly(L-lactide) (PLLA) modified with multiwall carbon nanotubes (MWCNT) and linear ladder-like poly(silsesquioxane) with methoxycarbonyl side groups (LPSQ-COOMe) were obtained. MWCNT and LPSQ-COOMe were added to the polymer solution before the electrospinning. In addition, nonwovens of PLLA grafted to modified MWCNT were electrospun. All modified nonwovens exhibited higher tensile strength than the neat PLA nonwoven. The addition of 10 wt.% of LPSQ-COOMe and 0.1 wt.% of MWCNT to PLLA increased the tensile strength of the nonwovens 2.4 times, improving also the elongation at the maximum stress.     

聚降冰片烯/聚乳酸共混物形状记忆效应的研究

将聚降冰片烯(PNB)和聚乳酸(PLA)按照PNB/PLA(80/20)、(70/30)、(60/40)、(50/50)4种不同质量配比进行共混,采用X射线衍射(XRD)、动态力学分析(DMA)、示差扫描量热分析(DSC)等对共混物基本性能进行表征,同时采用DMA-Q800对其形状记忆效应进行探究.结果显示:4种共混物均有明显屈服现象,随着PLA含量的增加,屈服现象越明显;PNB/PLA共混物出现2个玻璃化转变温度(T_g),且不随共混物配比变化而变化;4种共混物均在2θ=18.45o附近出现特征衍射峰,且其结晶度随PNB含量的减少而降低;随PNB含量的增多4种共混物的形状记忆性能提高.对于PNB/PLA(80/20),在双重形状记忆中,其形状固定率为99.88%,形状恢复率为81.04%;在三重形状记忆中,总固定率和恢复率分别为98.83%和94.26%.     

Poly(ether urethane) and poly(ether urethane urea) membranes with high H2S/CH4 selectivity

The objective of this study was to synthesize rubbery polymers with a high H₂S/CH₄ selectivity for possible use as membrane materials for the separation of H₂S from ‘low-quality’ natural gas. Two poly(ether urethanes), designated hereafter PU1 and PU3, and two poly(ether urethane ureas), designated PU2 and PU4, were synthesized and cast in the form of ‘dense’ (homogeneous) membranes. PU1 and PU2 contained poly(propylene oxide) whereas PU3 and PU4 contained poly(ethylene oxide) as the polyether component. The permeability of these membranes to two ternary mixtures of CH₄, CO₂, and H₂S was measured at 35°C, and for a PU4 membrane also at 20°C, in the pressure range from 4 to 13.6 atm (4.05–13.78×10⁵ Pa). PU4 is a very promising membrane material for H₂S separation from mixtures with CH₄ and CO₂, having a H₂S/CH₄ selectivity greater than 100 at 20°C as well as a very high permeability to H₂S. Permeability measurements were also made with commercial PEBAX^TM membranes for comparison. The possibility of upgrading low-quality natural gas to US pipeline specifications for H₂S and CO₂ by means of membrane processes utilizing both highly H₂S-selective and CO₂-selective polymer membranes is discussed.     

聚乳酸与聚丙撑碳酸酯共混体系的性能

采用熔融共混的方法制备了聚乳酸(PLA)/聚丙撑碳酸酯(PPC)共混物。DSC测试结果表明,纯PLA和PPC的玻璃化转变温度分别为54和37℃,不同组成的PLA/PPC共混物有2个明显的玻璃化转变温度,且与纯PLA和PPC的玻璃化转变温度相对应,说明二者是不相容体系。力学测试结果表明,当PPC质量分数超过20%时,可以看到明显的屈服点。共混物在拉伸过程中也有明显的颈缩、应力发白现象,表明随着PPC含量增加,PLA/PPC共混物由典型的脆性断裂向韧性转变。随着PPC含量的增加,共混物模量降低,断裂伸长率增加,当PPC质量分数为50%时,共混物的断裂伸长率达到最大值62%。共混物的粘度可在很宽的范围内予以调控,以满足不同加工的需要。     

磺化聚醚酰亚胺/聚醚砜共混型质子交换膜的制备及其性能

以磺化聚醚酰亚胺(SPEI)和聚醚砜(PES)为原料, 采用溶液共混法成功制备出了SPEI/PES共混型质子交换膜,并经热重分析、AFM、SEM等对膜的结构和性能进行了表征. 结果表明, 共混膜较纯SPEI膜具有更高的热稳定性和较低的溶胀性; 在室温环境下, 共混膜在干态和湿态时均具有优异的机械性能; 与纯SPEI膜相比, 共混膜的形态结构更为致密, 这将有利于降低甲醇的渗透性. 采用交流阻抗法和隔膜扩散法分别考察了膜的质子传导性和阻醇性能, 对于共混质量比为50/50的膜来说, 其质子传导率达到了5.5 mS·cm-1的水平, 能满足质子交换膜的需求, 但其甲醇渗透系数明显降低, 仅为市用Nafion 112膜的5%, 这表明该共混膜有望作为一种新型的直接甲醇燃料电池用质子交换膜.     

聚醚醚酮/聚醚醚酮酮共混体系的熔融和等温结晶行为

采用熔融共混方法制备了聚醚醚酮和聚醚醚酮酮的共混物,用DSC对共混物的熔融行为和等温结晶行为进行了研究.结果表明,共混物熔点随聚醚醚酮含量增加而降低,但与聚醚醚酮酮有相同的平衡熔点,二者共混没有改变其结晶的成核与生长机制.     

聚乳酸/聚己内酯/聚(ε-己内酯-L-丙交酯)共聚物三元共混体系的结构与性能

通过开环共聚合,合成了3种不同单元比例的ε-己内酯(ε-CL)与L-丙交酯(L-LA)的共聚物P(CL-co-LA)。通过熔融共混制备了聚乳酸(PLA)/聚己内酯(PCL)/P(CL-co-LA)三元共混材料,研究了P(CL-co-LA)对共混材料微观形貌、热性能以及力学性能的影响。 结果表明,共聚物P(CL-co-LA)作为PLA/PCL不相容体系的界面增容剂,减小了PCL分散相的尺寸,改善了PLA/PCL共混体系的相容性,提高了共混材料的韧性。 固定m(PLA):m(PCL):m(P(CL-co-LA))=80:20:10时,以P(CL49/LA51)(其中数字代表摩尔分数(%))作为界面增容剂效果最佳,共混材料的断裂伸长率可达到(210±30)%。     

形状记忆聚(乳酸-乙醇酸)(PLLGA)的制备及性能研究

采用开环聚合法合成了一系列具有不同组成的聚(乳酸-乙醇酸)(PLLGA)共聚物, 并通过红外光谱(FT-IR)、核磁共振氢谱(¹H NMR)、凝胶渗透色谱(GPC)、差示扫描量热分析(DSC)、X射线衍射分析(XRD)和拉伸试验, 对PLLGA共聚物的化学结构、相结构、热性能、力学性能和形状记忆性能进行了系统研究, 并分析了其形状记忆效应的微观机理. 研究表明, 通过调整PLLGA共聚物的组成, 可获得良好的力学性能和形状记忆效应. 对PLLGA90/10和80/20, 由结晶部分及大分子链之间的缠结点共同作为固定相, 无定型部分作为可逆相. 而对PLLGA70/30和60/40, 仅由大分子链之间的缠结点作为固定相, 其无定型部分均作为可逆相. 综合而言, PLLGA80/20具有最好的形状记忆效应.     

聚苯乙炔包覆多壁碳纳米管的制备及其分散性

用苯乙炔合成聚苯乙炔(PPA), 对多壁碳纳米管进行纯化、氧化, 然后将多壁碳纳米管与PPA一起在甲苯中超声分散. 结果显示氧化多壁碳纳米管已被PPA包覆且能够稳定分散于甲苯溶液中, 一个多月不沉降. 分别采用傅立叶变换红外(FTIR)光谱、酸碱滴定、拉曼光谱分析氧化后多壁碳纳米管的结构变化. 利用高分辨透射电镜(HRTEM)分别观察纯化、氧化、PPA包覆多壁碳纳米管的分散情况.     

新型聚醚聚氨酯/硬段模型化合物/高氯酸钠复合物的制备和表征

以聚醚聚氨酯和硬段模型化合物为聚合物基体,高氯酸钠为掺杂盐,合成了一系列新型的聚氨酯／硬段模型化合物／高氯酸钠复合物,利用FR－IR,DSC,AFM和复阻抗谱等表征手段对其形态和性能进行了基团和羰基都可与钠离子进行络合,温度变化可以导致不同程度的络合,在低盐浓度下,复合物的Tk随盐浓度的增加逐渐上升,而在一定的浓度之上,玻璃化转变温度又明显下降;通过调整盐的含量可以得到不同的表面形态。随着温度的升高,该体系的离子电导率显著增加。     

Micellization and Thermogelation of Poly(ether urethane)s Comprising Poly(ethylene glycol) and Poly(propylene glycol)

A series of multiblock poly(ether urethane)s comprising poly(ethylene glycol) (PEG), and poly(propylene glycol) (PPG) segments were synthesized. Their aqueous solutions exhibited thermogelling behavior at critical gelation concentrations (CGC) ranging from 8 to 12 wt%. The composition and structural information of the copolymers were studied by GPC and ¹H NMR. The critical micellization concentration (CMC) and thermodynamic parameters for micelle formation were determined at different temperatures. The temperature response of the copolymer solutions were studied and found to be associated with the composition of the copolymers.     

含联苯结构聚醚醚酮酮共聚物和共混物的制备及性能研究

聚醚醚酮（PEEK）是八十年代初投入市场的全芳香结构热塑性耐高温特种工程塑料，它的7’。一143“C，Tm一334C“‘，最大结晶度为48％，典型制品结晶度为20％～30％［”．PEEK可用通常的设备成型，其制件、纤维、涂料及复合材料在电子电器、机械设备、交通运输、宇航、原子能工程、军事等领域有广泛的用途［’j．聚醚醚酮酮（PEEKK）是继PEEK之后，由德国Hoechst公司开发出来的又一种全芳香结构热塑性耐高温特种工程塑料［‘j．为了研究该类聚合物的结构和性能的关系，我们在实验室中合成了PEEKK和含联苯结构聚醚醚酮酮（PE－＊…     

热塑性聚酰亚胺与聚醚醚酮共混物的等温结晶动力学

采用熔融共混方法制备了热塑性聚酰亚胺(TPI)与聚醚醚酮(PEEK)的共混物; 用示差扫描量热分析(DSC)研究了共混物的等温结晶动力学. 分别采用Avrami方程和Hoffman-Lauritzen方程分析共混物的等温结晶动力学、端表面自由能(σe)和分子链折叠功(q). 结果表明, 加入TPI后PEEK的结晶速率降低, 结晶活化能、σe和q均增加. 但这些数值的变化与TPI含量不呈线性关系, 并从共混物的相容性和表面形貌给出了可能的解释.     

超声引发自由基聚合制备聚苯乙烯磺酸钠接枝炭黑

通过在超声环境下,单体苯乙烯磺酸钠发生自由基聚合,生成的聚合物长链自由基被炭黑表面捕获,制备聚合物接枝炭黑.借助红外光谱、热重、粒度、透射电镜和zeta电位分析对该接枝炭黑进行表征.同时研究超声条件对接枝率的影响.结果表明,单体聚合并接枝到炭黑表面,同时炭黑的附聚体和一些大的聚集体结构被超声破碎,平均粒径大为减小;在300W超声波输出功率下,反应1h后,接枝率达到12.8%并趋于稳定.由于接枝分子链上磺酸基的存在,接枝炭黑在水中的分散稳定性显著改善.     

Preparation and Characterization of Poly(methyl methacrylate)-functionalized Carboxyl Multi-wall Carbon Nanotubes

"An in situ polymerization process was used to prepare poly (methyl methacrylate) (PMMA)-functionalized carboxyl multi-walled carbon nanotubes using carboxylate carbon nanotubes and methyl methacrylate as reactants and benzoyl peroxide as an initiator agent. The functionalized multi-walled carbon nanotubes were characterized using transmission electron microscope, scanning electron microscope, nuclear magnetic resonance, Fourier transform infrared spectroscopy, thermogravimetric analysis and Raman. The results indicate that the PMMA chains are covalently linked with the surface of carboxylate carbon nanotubes. The surface morphology is controlled by the content of carboxylate carbon nanotubes in the reactants. The PMMA functionalized multi-walled carbon nanotubes are soluble in deuterated chloroform. The storage modulus and tanffi magnitude increase as the content of CCNTs increases up to 0.3%."     

热塑性淀粉/聚丁二酸丁二醇酯合金的制备和结构性能表征

制备了高填充的甘油塑化淀粉（GTPS）/聚丁二酸丁二醇酯（PBS）合金,并对其结构性能进行了表征。结果表明：GTPS/PBS在合金加工过程中其扭矩以及力学性能随PBS质量分数的增加及甘油质量分数的减小而增大;扫描电镜（SEM）显示甘油可提高合金的相容性;动态力学分析（DMA）表明合金在玻璃态时的储存模量高于纯PBS,黏流态时则相反;合金的热稳定性随PBS和甘油质量分数的增加而有所提高;PBS的加入将合金的吸水率由100%以上降低到10%以下;淀粉和甘油的存在则均可提高PBS的降解率。     

Dynamics of Poly(vinylmethyl ether) Blends with a Strongly Interassociating Copolymer

We apply broadband dielectric relaxation spectroscopy to probe the dynamics of hydrogen bonded polymer blends. A copolymer consisting of 2,3-dimethylbutadiene (DMB) [86%] and p-(hexafluoro-2-hydroxyl-2-propyl)styrene (HFS) [14%] was synthesized and blended with poly(vinylmethyl ether) (PVME). The copolymer is capable of forming strong intermolecular hydrogen bonds, while minimizing the degree of intramolecular associations, and its blends with PVME are predicted to be miscible over the entire composition range. Two segmental processes, α and α₁, are present in blends containing 26, 50, and 76 weight percent copolymer. The slower process (α₁) is assigned to the segmental motion of the intermolecularly associated copolymer, and the faster process (α) to segmental motions of PVME modified by the HFS:DMB copolymer. A relaxation associated with residual water is present in the glassy state. A local process due to motions of the PVME ether groups (β) is also present in the glassy state, and does not change with blend composition.     

形状记忆聚偏氟乙烯/丙烯酸酯/碳纳米管纳米复合材料的导电及导热性能

利用聚偏氟乙烯（PVDF）微小结晶的物理交联点作用,制备了形状记忆性能优异的聚偏氟乙烯/丙烯酸酯聚合物（PVDF/ACM）共混材料,为提高其导电及导热性能,于其中引入了碳纳米管（CNT）,系统研究了PVDF/ACM/CNT三元体系纳米复合材料的导热及导电性能。 结果表明,碳纳米管在PVDF/ACM体系中分散均匀;在基本保持其形状记忆性能的前提下,碳纳米管的加入使材料导热性能及导电性能有较大程度的提高：质量分数为4%的CNT使材料25 ℃的电阻值降低至5000 Ω/square,导热系数提高至0.157 W/(m·K)。