OMMT对POE/POE-g-MAH/DB-AO/OMMT复合材料性能的影响

采用熔融插层法制备了乙烯-1-辛烯共聚物(POE)/马来酸酐(MAH)接枝POE(POE-g-MAH)/十溴二苯醚(DB)-三氧化二锑(AO)/有机蒙脱土(OMMT)复合材料。采用X射线衍射仪、透射电子显微镜分析了OMMT在POE/POE-g-MAH/DB-AO/OMMT复合材料中的分散形态,研究了OMMT与DB-AO的协效作用对复合材料阻燃性能和力学性能的影响。结果表明:OMMT片层均匀地分散在母粒中,达到了纳米级的分散,且大部分以剥离形态存在;当w(OMMT)在3%以内,复合材料的阻燃级别均为FV-0级;随着w(OMMT)增加,复合材料的热释放速率由964.58 kW/m2降到494.72 kW/m2,质量损失速率由0.285 g/s降到0.137 g/s,表明OMMT与DB-AO的协效作用能有效提高复合材料的阻燃性能;加入OMMT有利于提高复合材料的定伸应力和撕裂强度。     

OMMT分散形态对POE/OMMT复合材料性能的影响

用熔融插层法制备了乙烯-1-辛烯共聚物(POE)/有机蒙脱土(OMMT)复合材料和马来酸酐接枝POE(POE-g-MAH)/OMMT纳米复合材料.用透射电子显微镜(TEM)和X射线衍射(XRD)分析了OMMT在两种基体中的分散形态;采用热重(TG)分析仪和锥形量热仪研究了两种复合材料的热稳定性和阻燃性能,同时考察两种复...     

PP/M-HOS/POE三元复合材料的界面改性与力学性能

采用马来酸酐接枝聚丙烯(PP-g-MAH)及马来酸酐接枝乙烯-1-辛烯共聚物(POE-g-MAH)为界面相容剂，利用熔融共混法制备PP／镁盐晶须(M—HOS)／POE三元复合材料，研究了PP-g-MAH及POE-g-MAH的用量及配比、M-HOS和POE的用量对三元复合材料力学性能的影响。结果表明：当PP／M-HOS／POE的质量比为100／10／20时，PP-g-MAH的最佳用量为3份；利用PP-g-MAH及POE-g-MAH作为复合相容剂可同时改善M-HOS与PP和POE的界面相容性，促进POE、M-HOS对PP的增韧补强作用，使三元复合材料的力学性能得到了明显的改善。     

聚烯烃弹性体对剑麻纤维增强聚丙烯复合材料性能的影响

为提高剑麻(SF)增强聚丙烯(PP)复合材料的韧性,分别采取乙烯-辛烯共聚物(POE)和马来酸酐接枝POE(POE-g-MAH)二种弹性体对其进行增韧改性;研究了弹性体和纤维用量的变化对SF/PP/弹性体三元复合体系力学性能的影响及其内在原因。结果表明:POE和POE-g-MAH对剑麻增强聚丙烯复合材料均有良好的增韧效果;仅从增韧效果而言,在弹性体用量较低阶段POE优于POE-g-MAH,但当弹性体增至30%以后,POE-g-MAH则好于POE;在拉伸强度、拉伸模量、弯曲强度及弯曲模量方面,POE-g-MAH均比POE效果更好。     

PA11/POE/POE-g-MAH共混合金的制备及性能研究

通过熔融共混法制备了聚酰胺11/乙烯-辛烯共聚物/马来酸酐接枝乙烯-辛烯共聚物(PA11/POE/POE-g MAH)三元共混合金,研究了POE-g-MAH及混合弹性体(POE/POE-g-MAH)的用量对该合金力学性能的影响。利用扫描电子显微镜(SEM)观察了PA11/POE/POE-g-MAH合金的冲击断面形貌,并采用动态热机械分析仪(DMA)表征了该合金材料的动态力学性能。结果表明:当混合弹性体POE/POE-g-MAH的配比为4/3,且其用量为25%时,PA11/POE/POE-g-MAH合金的综合力学性能最佳。适量POE-g-MAH的加入有助于弹性体分散相的细化,从而使弹性体粒子的粒径分布趋于均一,且分散均匀,并改善了PA11与混合弹性体间的相容性。混合弹性体与PA11共混后,能显著降低材料的动态储能模量,提高材料的韧性。     

POE-g-MAH对PA66/纳米TiO_2复合材料力学性能及相容性的影响

采用熔融共混法制备了尼龙(PA)66/马来酸酐接枝乙烯-辛烯共聚物(POE-g-MAH)/纳米TiO2复合材料,通过万能材料试验机、冲击试验机、熔体流动速率(MFR)测试仪等研究了POE-g-MAH对复合材料力学性能及MFR的影响,利用Molau实验和FSEM考察了POE-g-MAH与PA66的相容性。结果显示,POE-g-MAH与PA66基体有很好的相容性;随着POE-g-MAH用量的增加,PA66/POE-g-MAH/纳米TiO2复合材料的缺口冲击强度逐渐增加,拉伸强度、弯曲强度、拉伸弹性模量及MFR逐渐降低;当POE-g-MAH质量分数为12%时,复合材料的综合性能最佳,缺口冲击强度、拉伸强度、弯曲强度、拉伸弹性模量和MFR分别为20.89kJ/m2,41.15MPa,64.2MPa,1428.15MPa和19.2g/(10min)。     

尼龙-6/蒙脱土纳米复合材料用POE-g-MAH改性及性能研究

制备了尼龙-6(PA6)/马来酸酐接枝乙烯-1-辛烯共聚物(POE-g-MAH)和PA6-蒙脱土纳米复合物(NCH)/POE-g-MAH两种复合材料,其脆韧转变点都是在POE-g-MAH质量分数为8%～10%。在脆韧转变点前,PA6/POE-g-MAH和NCH/POE-g-MAH的缺口冲击强度几乎相同;在脆韧转变点后,NCH/POE-g-MAH的冲击强度远高于PA6/POE-g-MAH。复合材料的拉伸强度都随POE-g-MAH的增加而线性下降,在相同POE-g-MAH含量时,NCH/POE-g-MAH的拉伸强度比PA6/POE-g-MAH的低4MPa左右。     

LDPE/树脂镜片磨屑粉/POE-g-MAH复合材料的相容性和力学性能研究

考察了乙烯-辛烯共聚物接枝马来酸酐(POE-g-MAH)、树脂镜片磨屑粉用量对低密度聚乙烯(LDPE)/树脂镜片磨屑粉/POE-g-MAH复合材料的力学性能的影响,并研究了共混体系的相容性。力学性能测试表明,POE-g-MAH加入提高了复合材料的抗冲击性能;LDPE/树脂镜片磨屑粉/POE-g-MAH复合材料的拉伸强度随着树脂镜片磨屑粉用量增加而上升,冲击强度在树脂镜片磨屑粉用量为100份时达到最大值。红外光谱表明,POE-g-MAH与树脂镜片磨屑粉共混时发生酯化反应。电镜观察揭示了用POE-g-MAH增容的复合材料有更好的界面相容性。     

POE-g-MAH对聚丙烯/竹纤维复合材料性能的影响

将聚丙烯(PP)﹑竹纤维(BF)与马来酸酐接枝乙烯-辛烯共聚物(POE-g-MAH)共混,通过双螺杆挤出机制备PP/POE-g-MAH/BF复合材料,用扫描电子显微镜、X射线衍射仪和差示扫描量热仪观察和表征了其形貌、结构和结晶参数,测试了其力学性能。研究表明,加入POE-g-MAH,降低了BF质量分数为30%的PP/BF复合材料中PP晶相的完整程度,明显提高了复合材料的冲击强度,改善了PP基体中BF的分散均匀性。添加质量分数2.5%的POE-g-MAH,能进一步提高PP/BF复合材料的强度和韧性,PP/POE-g-MAH/BF(62.5/7.5/30)复合材料的冲击强度高于纯PP。冲击强度的提高主要源于POE-g-MAH所产生的能量耗散、改善应力的有效传递、增强BF和PP的界面粘附。     

EPDM/POE/PP热塑性硫化橡胶材料的制备及性能研究

以三元乙丙橡胶(EPDM)/乙烯-辛烯共聚物(POE)/聚丙烯(PP)为原料,在PP含量固定的情况下,将POE部分取代EPDM,采用动态硫化技术制备出EPDM/POE/PP三元热塑性橡胶材料(TPV),研究不同含量的POE对材料力学性能、流变性能和微观形貌的影响。结果显示,随着POE含量的增加,三元TPV材料的硬度和熔体质量流动速率不断增大;拉伸强度和断裂伸长率呈线性增大,当EPDM/POE/PP比例为45/40/15时,材料力学性能达到最大值。流变性能和微观形貌分析结果表明,EPDM/POE/PP三元TPV材料具有良好的综合性能。     

丙烯酸酯与丙烯酰胺共聚物表面活性剂的合成

研究了烷基酚聚氧乙烯醚丙烯酸酯活性大单体的合成。以ＤＭＦ为溶剂,过氧化物为引发剂,烷基酚聚氧乙烯醚丙烯酸酯（ＡＥ）、丙烯酰胺（ＡＭ）和丙烯酸异辛酯（ＭＧ）共聚,得到了三元共聚物（ＡＥＡＭＭＧ）高分子表面活性剂,探讨了单体组成、引发剂和溶剂用量、反应温度对共聚物表面活性和粘度的影响。结果表明,ＡＥＡＭＭＧ共聚物表面高,增粘能力强,１％共聚物水溶液的表面张力低达３２．４ｍＮ／ｍ,油水界面张力小于１ｍＮ     

三种有发展前景的制备热塑性弹性体的方法

综述了三种有发展前景的合成热塑性弹性体的方法,包括阳离子共聚法、大分子单体与小分子单体共聚法及乳液接技共聚法,并讨论了其产物的结构与性能的关联.     

Preparation and properties of semifluorinated block copolymers of 2-(dimethylamino)ethyl methacrylate and fluorooctyl methacrylates

Semifluorinated block copolymers of poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) and poly(fluorooctyl methacrylates) (PFOMA) were prepared using group transfer polymerisation via sequential monomer addition. Wide ranges of copolymers were obtained with good control over both molecular weight and composition by adjusting the monomers/initiator ratio. The micellar characteristics of the copolymers in water and chloroform were investigated by quasi-elastic light scattering and transmission electron microscopy. The size and morphologies of micelles were greatly influenced by copolymer composition, pH, and temperature. In addition, the solubility of copolymers and the formation of water-in-carbon dioxide (W/C) microemulsions were described in terms of the cloud points. The block copolymers exhibited the excellent ability of stabilizing W/C microemulsions.     

Effect of composition of added random copolymer on the phase behavior of block copolymer

Blends of styrene-butadiene diblock copolymer (S-B, 52 wt% styrene content) and styrene-butadiene random copolymer (SBR) of various styrene compositions were studied by small-angle X-ray scattering, light scattering, and transmission electron microscopy. The composition of random copolymer plays an important role in the solubilization of SBR in S-B. The order-disorder transition temperature, T_ODT, decreases linearly with the addition of SBR. T_ODT decreases as the symmetry in SBR composition increases and shows the highest value in the case of homopolymers. Asymmetric butadiene-rich SBR dissolves mostly into PB microdomain of S-B to increase lamella microdomain spacing, D, and its addition makes the overall microdomains of S and B in the mixture more asymmetrical. Symmetric SBR is localized into the interface of S-B microdomain to reduce unfavorable S-B contact at the interface. The phase diagram for S-B containing asymmetric SBR shows a succession of mixed mesophases of different morphologies from lamellae and cylinder to disordered liquid phases, whereas the phase diagram containing symmetric SBR shows two homogeneous phases and one region of two-phase coexistence, where macroscopically separated phases coexist together.     

傅立叶变换红外光谱法快速测定乙丙共聚物中的乙烯含量

研究了用傅立叶变换红外光谱法测定乙丙共聚物中乙烯含量的方法。建立了傅立叶红外光谱法快速测定乙丙共聚物中乙烯含量的标准工作曲线,对其准确性和精密度进行了评价。结果表明,测定样品的最大相对误差为2.82%,重复测定同一样片的相对标准偏差为0.48%,方法的准确性和精密度良好。该方法适用于乙烯质量分数为0%~33%的乙丙无规共聚物和嵌段共聚物的测定,并且已在生产中得到很好的应用。     

Surface properties of block and graft polystyrene–polydimethylsiloxane copolymers

The surface compositions of a series of polystyrene‐b‐polydimethylsiloxane (PS‐b‐PDMS) and polystyrene‐g‐polydimethylsiloxane (PS‐g‐PDMS) copolymers were investigated using ATR‐FTIR and XPS technique. The results showed that enrichment of PDMS soft segments occurred on the surface of the block copolymers as well as on that of graft copolymers. And the magnitude order of the enrichment was as follows: PS‐b‐PDMS > PS‐g‐PDMS, which was attributed to the facilitating of the movement of the PDMS segments in PS‐b‐PDMS copolymer. Meanwhile, the solvent type and the contact medium had influence on the accumulation of PDMS on the surfaces. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Micellization of synthetic and polysaccharides-based graft copolymers in aqueous media

This review highlights recent advances in the micellization of synthetic graft copolymers and those based on natural precursors, particularly polysaccharides. Synthesis and characterization of a broad range of architectures are discussed, along with different micellization procedures and fundamental micellar characteristics, such as morphology and size. Micelle formation by synthetic graft copolymers in aqueous media is examined in detail for different architectures of nonionic, ionic, and temperature and pH stimuli-responsive “double hydrophilic” copolymers. In this context, the problems associated with unimolecular micelles and the correlations between molecular characteristics are further addressed. In addition to backbone and side chain molecular weights, grafting density and topology are the major parameters that directly influence graft copolymer micellization. A similar overview is provided for graft copolymers based on polysaccharides, such as cellulose, chitosan, dextran, and starch. Finally, an outlook is given on the prospects for further development in this area.     

Calorimetric study of block-copolymers of poly(n-butyl acrylate) and gradient poly(n-butyl acrylate-co-methyl methacrylate)

The nanophase separation in diblock and triblock copolymers consisting of immiscible poly(n-butyl acrylate) (block A) and gradient copolymers of methyl methacrylate (MMA) and n-butyl acrylate (nBA) (block M/A) were investigated by means of their heat capacity, C_p, as a function of the composition of the blocks M/A and temperature. In all copolymers studied, both blocks are represented by their C_p and glass transition temperature, T_g, as well as the broadening of the transition-temperature range. The low-temperature transition of the blocks A is always close to that of the pure poly(n-butyl acrylate) and is independent of the analyzed compositions of the block copolymer, but broadened asymmetrically relative to the homopolymer due to the small phase size. The higher transition is related to the glass transition of the copolymer block of composition M/A. Besides the asymmetric broadening of the transition due to the phase separation, it decreases in T_g and broadens, in addition, symmetrically with increasing acrylate content. The concentration gradient is not able to introduce a further phase separation with a third glass transition inside the M/A block.     

Optimizing Chain Topology of Bottle Brush Copolymer for Promoting the Disorder-to-Order Transition

The order-disorder transitions (ODT) of core-shell bottle brush copolymer and its structural isomers were investigated by dissipative particle dynamics simulations and theoretically by random phase approximation. Introducing a chain topology parameter λ which parametrizes linking points between M diblock chains each with N monomers, the degree of incompatibility at ODT ((χN)ODT; χ being the Flory–Huggins interaction parameter between constituent monomers) was predicted as a function of chain topology parameter (λ) and the number of linked diblock chains per bottle brush copolymer (M). It was found that there exists an optimal chain topology about λ at which (χN)ODT gets a minimum while the domain spacing remains nearly unchanged. The prediction provides a theoretical guideline for designing an optimal copolymer architecture capable of forming sub-10 nm periodic structures even with non-high χ components.     

Theoretical study on morphology of ABCD 4-miktoarm star block copolymer

A real-space implementation of the self-consistent field theory (SCFT) has been used to study the morphologies of ABCD 4-miktoarm star block copolymers. For the sake of numerical tractability, the morphologies and the phase diagrams of ABCD 4-miktoarm star block copolymers are investigated in two dimensions (2D) by varying the volume fractions of the blocks and the interaction parameters. Many interesting and complex morphologies occur and compared with ABCD linear block copolymers; ABCD 4-miktoarm star block copolymers have more regular disciplines. We found that systems with similar components have similar morphologies and at the weaker segregation, the minority components always cannot separate from the other blocks and they easily dissolve to form one phase with other block(s), but with the increase of the segregation degree (large ), the ordered phases can be well separated. With the help of our computational prediction, experimental researchers can work more purposefully and efficiently.