聚苯乙烯的刚性无机粒子增韧

讨论了刚性无机粒子在增韧聚苯乙烯塑料中的增韧机理、影响因素及其应用。通过讨论得出结论,无机纳米粒子的出现,将会大大促进无机刚性粒子在塑料增韧方面的应用。     

Toughening mechanism of SAN resin

SAN resin poly(styrene-co-acrylonitrile) combine, the gloss and transparency of PS with added chemical resistance, high heat distortion temperature, dimensional stability and stiffness characteristics. However brittleness restricts its wider application. The morphology, impact behavior and toughening mechanism of four rubbers toughened SAN resin were investigated in this study.     

我国聚氯乙烯增韧改性研究的最新进展

介绍了当前国内弹性体及刚性粒子增韧聚氯乙烯的研究现状及发展方向。     

粉末NBR对PVC的增韧作用

用交联包覆法制备的粉末丁腈橡胶（ＰＮＢＲ） 与ＰＶＣ 共混。研究了ＰＮＢＲ 的性质及用量对共混体冲击强度的影响。发现线型ＰＮＢＲ 对ＰＶＣ 有显著的增韧作用,当其用量（ 质量） 为１０ 份,共混体的Ｃｈａｒｐｙ 缺口冲击强度达７１ｋＪ／ ｍ ２ 。ＰＮＢＲ大分子的交联结构与包覆剂的存在会稍为降低共混体的冲击强度。共混体的脆韧转变发生在ＰＮＢＲ 用量（ 质量） 为７ ．５ ～１０ 份之间。共混体冲击断面形貌的ＳＥＭ 分析表明其增韧机理为剪切屈服机理。     

Toughening vinyl ester networks with polypropylene meso-fibers: Interface modification and composite properties

Polymer-polymer composites comprised of vinyl ester matrices (VE) and polypropylene (PP) fiber meshes were fabricated and tested in this investigation. Results indicated that PP fibers greatly enhanced fracture toughness; however, strength of the VE was significantly reduced as voids were observed at the interface of the PP and VE. A two-step surface modification, oxygen plasma treatment followed by grafting vinyltrimethoxysilane (VTMS), was conducted on PP fibers in an effort to improve interfacial strength. Interfacial discontinuities of composites were improved after surface modification of PP. The oxygen plasma treatment added hydrophilic functional groups but caused surface roughness. Surface treatment of PP slightly increased fracture toughness of the PP-VE composite by enhancing energy absorption capacity at the interface. However, mechanical strength and modulus did not significantly increase for the composite using VTMS grafted PP fibers due to the weak fiber material. Small PP fibers with higher strength may attain the expected improvement in mechanical properties after surface treatment.     

阻燃高抗冲聚苯乙烯的增韧研究

分别以SBS、EPDM、EVA为增韧剂,研究了它们对阻燃高抗冲聚苯乙烯物理机械性能和阻燃性能的影响。结果表明,以SBS为增韧剂所得复合材料的综合性能优于以EPDM或EVA为增韧剂所得复合材料的综合性能;复合材料的冲击强度随SBS用量的增加而增大。当SBS质量分数为18％时,其冲击强度达到10kJ／m^2左右,较未经增韧改性复合材料的冲击强度增加了8kJ／m^2左右,并且SBS的加入不会对复合材料的阻燃性能产生不利影响。     

CPE,CV及其与ACR,MBS复合增韧RPVC的研究

考察了不同ＣＰＥ牌号及用ＣＰＥ－ＰＶＣ接枝共聚物（ＣＶ）部分或全部代替ＣＰＥ对改善Ｒ－ＰＶＣ冲击和拉伸性能的影响,在此基础上,研究了复合增韧体系（ＣＰＥ、ＣＶ分别与ＡＣＲ、ＭＢＳ并用或ＣＰＥ、ＣＶ同时和ＡＣＲ并用等）对提高Ｒ－ＰＶＣ力学性能的影响。结果表明,ＣＰＥ的分子量高、氯含量分布窄和氯含量高、残余结晶度高分别对提高Ｒ－ＰＶＣ的冲击和拉伸强度有利;ＣＶ与ＣＰＥ并用能提高Ｒ－ＰＶＣ的冲击强度,并且拉伸强度的损失较单独使用ＣＰＥ为小,并用时其组成比以１１为宜;ＣＰＥ、ＣＶ与ＡＣＲ或ＭＢＳ联合使用,在适宜组成比下能对Ｒ－ＰＶＣ产生协同增韧效应,改善体系的相容性,提高冲击性能并保留较高的其它力学强度,这是解决目前ＰＶＣ／ＣＰＥ共混材料性能缺陷的有效方法。     

Toughening of polypropylene by combined rubber system of ultrafine full-vulcanized powdered rubber and SBS

A combined rubber system of ultrafine full-vulcanized powdered rubber (UFPR) and SBS was used for polypropylene toughening. The PP toughened with the combined rubber system shows not only higher impact strength as compared to each rubber component used alone but also good stiffness and heat resistance. Crystallization study shows that the UFPR is more efficient in promoting the crystallization of PP than SBS, leading to a higher crystallinity and an enhancement of stiffness and heat resistance of PP. The combined rubber system containing UFPR and a small amount of SBS still possesses a good nucleating ability. Transmission electron microscopy results indicate that the combined rubber system mostly forms an encapsulation structure of UFPR particles encapsulated by SBS phase. This morphology was also confirmed by scanning electron microscopy results through observing the fracture surfaces of toughened samples. A small amount of SBS was found to be helpful for a better dispersion of UFPR in PP matrix. The causes for the encapsulation morphology and the synergistic toughening effect were discussed. A tentative explanation was given by comparison of the solubility parameter of each component in the toughened samples.     

以PVC为外壳层的ACR抗冲改性剂的合成及其对PVC的增韧作用

以聚丙烯酸丁酯(PBA)为内核,通过种子乳液聚合制备了分别以聚甲基丙烯酸甲酯(PMMA)、聚氯乙烯(PVC)、PMMA/PVC为壳层的纯丙烯酸酯(ACR)和PVC改性ACR乳液.扫描电镜观察发现,纯ACR乳胶粒子具有明显的核-壳结构,进一步包覆PVC后形成疏松外层.考察了不同结构ACR与PVC共混物的相态结构、抗冲性能和断面形貌,发现用PVC部分或完全替代PMMA壳层的改性ACR在PVC基体分散良好,具有与纯ACR相当的增韧PVC作用,冲击断面呈现典型的韧性断裂特征.     

Mechanical properties and morphologies of polypropylene with different sizes of calcium carbonate particles

Three polypropylene (PP) matrixes with different intrinsic toughness were used to study the morphologies and mechanical properties of PP filled with four sizes of calcium carbonate particles. PP1 was a homopolymer, PP2 was a propylene‐ethylene copolymer, and PP3 was a mixture of PP1 and PP2 (PP1:PP2 = 1:1, weight ratio). Calcium carbonate (CC25, CC4, CC1.8, and CC0.07) with an average particle size of 25, 4, 1.8, and 0.07 μm, respectively, was used. It was clear that the PP matrix and filler size had key effects on improvement of mechanical properties of PP matrix. For all three PP matrixes, the yield strength, the flexural strength and modulus of the composites filled with CC25, CC4, and CC1.8 could be regarded as the same. But the yield strength, the flexural strength and modulus of composites filled with CC0.07 were obviously lower than those of composites filled with other sizes of particles. Among four sizes of calcium carbonate particles, CC0.07 had the best toughening effect to improve the impact strength of PP matrix, and the toughening effect of CC0.07 was influenced by PP matrix. For all PP matrixes, only in the case of moderate matrix toughness (PP3 matrix), the composite could receive the highest extent of toughness increase (4.3 times that of matrix). With regard to all PP composites, the best combination of properties was PP2 nanocomposite filled with 20 wt% CC0.07. POLYM. COMPOS., 27:443–450, 2006. © 2006 Society of Plastics Engineers     

Melt strength of calcium carbonate filled polypropylene melts

This paper investigates the extensional rheology (through melt strength measurement) of calcium carbonate (CaCO₃) filled polypropylene (PP) melts. Different concentrations of CaCO₃ filled PP were produced by mixing two master batches of pure PP and 70 wt% CaCO₃ filled PP in required proportions in a counter‐rotating twin‐screw extruder. It was found that the melt strength of the CaCO₃–PP melts was independent of CaCO₃ concentrations up to 25 vol%. Further increase in CaCO₃ concentration led to a severe reduction of melt strength. © 2002 Society of Chemical Industry     

Toughening of aromatic epoxy via aliphatic epoxy copolymers

While aromatic diglycidyl ether of bisphenol A (DGEBA) based epoxy polymer matrix systems are important for high-performance applications, their brittle nature is an issue that needs to be addressed. In this paper the authors show that small additions of a more flexible aliphatic epoxy copolymers, both di- and tri-functional, can significantly increase the notched Izod impact strength (56–77%) over the neat DGEBA, while not detrimentally affecting other mechanical properties such as glass transition temperature and flexural properties. In fact, at 1 wt% concentrations, the tri-functional epoxy shows a slight increase (∼2%) in the glass transition temperature compared to neat DGEBA. The improvement in impact toughness is attributed to the more flexible backbone of the aliphatic epoxy molecules. The total miscibility of the aromatic and aliphatic epoxies within the investigated concentration range (up to 20 wt%) allows for this toughening approach to be directly applied to current composite production methods, such as resin transfer molding (RTM).     

Toughening isotactic polypropylene and propylene-ethylene block copolymer with styrene-ethylene butylene-styrene triblock copolymer

Dynamic mechanical properties, low-temperature impact behavior, flexural modulus and heat distortion temperature (HDT) of isotactic polypropylene (i-PP) and propylene-ethylene block copolymer (Co-PP) toughened with styrene-ethylene butylene-styrene triblock copolymer (SEBS), at blending ratios of 0–30 phr, were studied and compared. A scanning electron microscopic morphology study of the impact-fractured surfaces demonstrated the changes in fracture mechanisms at various temperatures and SEBS contents. SEBS remarkably improves the impact endurance in the lower-temperature range when blended with Co-PP in comparison with i-PP, due to the increased compatibility in the interface between SEBS particles and the Co-PP matrix.     

PC及PC/ABS合金的增韧研究

研究了增韧剂SWR-7A对PC及PC／ABS增韧效果。比较了增韧剂SWR-7A与美国增韧剂GE-338及国内外其它增韧剂的增韧效果。研究表明，加入SWR-7A在提高PC及PC／ABS共混体系的冲击强度的同时，拉伸强度、弯曲强度及弯曲模量降低较少，达到了优化材料性能的目的，SWR-7A是一种理想的增韧剂。     

高抗冲聚苯乙烯的阻燃及增韧研究

采用十溴二苯醚(DBDPO)和三氧化二锑(Sb_2O_3)为阻燃复合体系对高抗冲聚苯乙烯(HIPS)进行阻燃改性,研究了阻燃复合体系对HIPS共混材料阻燃性能和力学性能的影响.结果发现:当DBDPO与Sb_2O_3的质量比为3:1时,HIPS共混材料的氧指数达到28%,阻燃效果较好,同时力学性能损失较小;加入无机阻燃剂可以抑制HIPS共混材料燃烧,明显降低发烟量;并比较了增韧剂种类和用量对HIPS共混材料阻燃性能和力学性能的影响.     

有机刚性粒子增韧聚苯硫醚的研究

采用有机刚性粒子聚甲基丙烯酸甲酯(PMMA)增韧改性聚苯硫醚(PPS)。考察了加工温度及PMMA用量对聚苯硫醚复合材料微观形态结构和力学性能的影响。结果表明,复合材料的力学性能随着加工温度的升高而下降。PMMA与PPS基体以“海岛”状的形式存在;少量PMMA加入时,PMMA同PPS结合较好,冲击强度显著提高;当增加PMMA的用量时,PMMA在PPS基体中的相区尺寸增大,界面变得明显,各项力学性能有小幅下降。     

Role of interfacial adhesion strength on toughening polypropylene with rigid particles

The effects of interfacial adhesion strength on the mechanical properties of composites of polypropylene and glass particles were investigated. The 3.5 μm average diameter glass particles were surface-treated using two silanes with different functional groups. The functional groups were hydrocarbons, expected to promote adhesion between filler and matrix, and fluorocarbons, expected to reduce the strength of adhesion. Mixtures of the functional groups were also used to treat the surface of the glass to obtain better control of adhesion strength and thus the mechanical properties of the composites. A model study using glass slides and polypropylene films was conducted to confirm the feasibility of treatment. Adhesion strength between glass and polypropylene increased with increasing coverage of the hydrocarbon silanes. The surface-modified particles were incorporated into the polypropylene matrix via melt processing. While surface functionalization of the particles can influence the dispersion of the particles, no significant effect was observed in this study. Tensile tests and toughness tests were performed on injection-molded samples. The tensile strength of the reinforced polypropylene increased with increasing adhesion strength. Impact toughness increased with weaker adhesion but the dependence became less pronounced as deformation rate was increased.     

Comparison of the toughening behavior of nylon 6 versus an amorphous polyamide using various maleated elastomers

The toughening effect of two types of elastomers based on ethylene/α-olefin copolymers, viz, an ethylene/propylene copolymer (EPR) with its maleated version, EPR-g-MA, and an ethylene/1-octene copolymer (EOR) with its maleated versions, EOR-g-MA-X% (X=0.35, 1.6, 2.5), for two classes of polyamides: semi-crystalline nylon 6 versus an amorphous polyamide (Zytel 330 from DuPont), designated as a-PA, was explored. The results are compared with those reported earlier based on a styrenic triblock copolymer having a hydrogenated midblock, SEBS, and its maleated version, SEBS-g-MA, elastomer system. Izod impact strength was examined as a function of rubber content, rubber particle size and temperature. All three factors influence the impact behavior considerably for the two polyamide matrices. The a-PA is found to require a somewhat lower content of rubber for toughening than nylon 6. Very similar optimum ranges of rubber particle sizes were observed for ternary blends of EOR-g-MA/EOR with each of the two polyamides while blends based on mixtures of EPR-g-MA/EPR and SEBS-g-MA/SEBS (where the total rubber content is 20% by weight) show only an upper limit for a-PA but an optimum range of particle sizes for nylon 6 for effective toughening. Higher EPR-g-MA contents lead to lower ductile-brittle transition temperatures (T_db) as expected; however, a-PA binary blends with EPR-g-MA have a much lower T_db than do nylon 6 blends when the content of the maleated elastomer is not high. A minimum in plots of ductile-brittle transition temperature versus particle size appears for ternary blends of each of the matrices with EOR-g-MA/EOR; blends based on SEBS-g-MA/SEBS, in most cases, show higher ductile-brittle transition temperatures, regardless of the matrix. However, blends with EPR-g-MA/EPR show comparable T_db with those based on EOR-g-MA/EOR for the amorphous polyamide but show the lowest ductile-brittle transition temperatures for nylon 6 within the range of particle sizes examined. For the blends with a bimodal size distribution, the global weight average rubber particle size is inappropriate for correlating the Izod impact strength and ductile-brittle transition temperature. In general, trends for this amorphous polyamide are rather similar to those of semi-crystalline nylon 6.     

新型增韧剂在尼龙6上的应用

比较了增韧剂I-NY与橡胶类、聚烯烃类增韧剂对尼龙6性能的影响。结果表明，随着增韧剂I-NY用量的增加，尼龙6的缺口冲击强度显著提高，当其质量分数为15％时，缺口冲击强度为28kJ／m^2，是纯尼龙6的10倍；且在改善冲击强度的同时，材料的弯曲和拉伸强度下降较少，是一种比较理想的尼龙增韧剂。     

Toughening of dimethacrylate resins by addition of ultra high molecular weight polyethylene (UHMWPE) particles

The effects of the addition of UHMWPE particles, of nominal 〈80 μm〉 size, on the fracture toughness, flexural modulus and strength of composites made with dimethacrylate resins (60/40 wt/wt BisGMA-TEGMA) were investigated as a function of volume fraction of UHMWPE (0-60 vol%) and particle surface treatment. Interfacial shear strengths (τ) were measured via microbond shear strength tests using Spectra900™ (UHMWPE) fibers and BisGMA-TEGMA beads. τ increased by a factor of 4 compared with untreated UHMWPE, and surface treated particles improved the mechanical properties of the composite. Fracture toughness (K_IC) and flexural modulus (E) increased with increased volume fraction of UHMWPE, with maximum K_IC/E increases (at 60 vol%) of 238%/25% compared with the neat resin. SEM images showed debonding as well as yielding and fibrillation of the UHMWPE particles, suggesting that these were significant toughening mechanisms.