Toughening and Compatibilization of Acrylonitrile–Butadiene–Styrene/Poly (Ethylene Terephthalate) Blends Using an Oxazoline-Functionalized Impact Modifier

An oxazoline-functionalized core–shell impact modifier was synthesized between aminoethanol and acrylonitrile/butadiene/styrene high rubber powder. According to the Fourier transform infrared spectroscopy test, the nitrile groups were partially converted into oxazoline groups successfully. The oxazoline-functionalized acrylonitrile/butadiene/styrene high rubber powder was used as an impact modifier for acrylonitrile–butadiene–styrene/poly(ethylene terephthalate) blends. The differential scanning calorimeter and rheological tests demonstrated that poly(ethylene terephthalate) was partially miscible with acrylonitrile–butadiene–styrene, because the oxazoline groups of oxazoline-functionalized acrylonitrile/butadiene/styrene high rubber powder reacted with the end groups of poly(ethylene terephthalate). The results of scanning electron microscopy indicated that the morphology of acrylonitrile–butadiene–styrene/poly(ethylene terephthalate) blends with proper oxazoline-functionalized acrylonitrile/butadiene/styrene high rubber powder content was improved significantly. The best mechanical properties were achieved, When 6 wt% oxazoline-functionalized acrylonitrile/butadiene/styrene high rubber powder was added into acrylonitrile–butadiene–styrene/poly(ethylene terephthalate) blends.     

Functionalization of polypropylene with oxazoline and reactive blending of PP with PBT in a corotating twin-screw extruder

The aim of this study was to prepare a compatibilized PP/PBT blend in a twin-screw extruder, using oxazoline-functionalized PP. First we prepared the functionalized PP (PP-g-OXA), and then we used it as a compatibilizer in the subsequent reactive blending stage. Polypropylene was successfully functionalized by ricinoloxazoline maleinate in a corotating twin-screw extruder using a melt free radical grafting technique. Grafting yields up to 2.1 phr were achieved. This functionalized PP used as a compatibilizer markedly improved the mechanical properties of the uncompatibilized PP/PBT (PBT content 30 wt %) blend. Significant improvements were observed, especially in impact strength (Charpy) and elongation at break of the compatibilized blends. The increased interactions between the phases were characterized by SEM analysis, DMTA, and DSC experiments. The properties of the blend greatly depended on the degradation of the PP during grafting. An optimal content of compatibilizer exists, which is dependent on the degradation of PP, grafting yield of oxazoline monomer, and on the amount of free, ungrafted monomer present in the compatibilizer. These factors can be adjusted by properly choosing the processing conditions and chemical parameters. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 883–894, 1997     

Thermal,morphological, and mechanical characteristics of polypropylene/polybutylene terephthalate blends with a liquid crystalline polymer or ionomer

Thermotropic side‐chain liquid crystalline polymer (SLCP) and corresponding side‐chain liquid crystalline ionomer (SLCI) containing sulfonate acid were used in the blends of polypropylene (PP) and polybutylene terephthalate (PBT) by melt‐mixing respectively, and thermal behavior, morphological, and mechanical properties of two series of blends were investigated by differential scanning calorimetry, Fourier transforms infrared spectroscopy (FTIR), scanning electron microscopy, and tensile measurement. Compared with the immiscible phase behavior of PP/PBT/SLCP blends, SLCI containing sulfonate acid groups act as a physical compatibilizer along the interface and compatibilize PP/PBT blends. FTIR analyses identify specific intermolecular interaction between sulfonate acid groups and PBT, and then result in stronger interfacial adhesion between these phases and much finer dispersion of minor PBT phase in PP matrix. The mechanical property of the blend containing 4.0 wt % SLCI was better than that of the other blends. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4712–4719, 2006     

Impact-modified poly(styrene-co-acrylonitrile) blends containing both oxazoline-functionalized poly(ethene-co-1-octene) elastomers and poly(styrene-co-maleic anhydride) as compatibilizer

Blends of a poly(styrene-co-acrylonitrile) (SAN) with poly(ethene-co-1-octene) rubber (EOR) were investigated. An improved toughness–stiffness balance was obtained when adding as a compatibilizer a blend consisting of oxazoline-functionalized EOR, prepared by grafting EOR with oxazoline-functional maleinate, and poly(styrene-co-maleic anhydride) (SMA), which is miscible with SAN. Enhanced interfacial adhesion was evidenced by the improved dispersion of the EOR in the SAN matrix and the reduced glass transition temperature of the dispersed EOR phase. Morphology studies using transmission electron microscopy revealed formation of an interphase between the matrix and the rubber particles. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 1685–1695, 1999     

氢化丁腈橡胶及其加工应用

氢化丁腈橡胶(HNBR)是国外近年来开发成功的一种物理机械性能优异、耐高温、耐臭氧、抗液体腐蚀性能极好的专用弹性体。主要适用于汽车制造、油井、军事及飞机制造等工业领域中。目前世界市场上只有Therban(联邦德国Bayer公司)、Toynal(加拿大Polysar公司)和Zelpol(日本Zeon公司)等几个商品牌号。本文拟以Therban为例,着重对HNBR的基本性能和加工应用性能作一探讨。     

Surface modification effects of core–shell rubber particles on the toughening of poly(butylene terephthalate)

We toughened poly(butylene terephthalate) (PBT) by loading core–shell rubber (CSR) type impact modifiers, consisting of a rubbery poly(n‐butyl acrylate) core and a rigid poly(methyl methacrylate) shell. To optimize the dispersion of CSR particles into the PBT matrix during melt compounding, the shell surface was modified with different grafting ratios of glycidyl methacrylate (GMA) reactive with PBT chain ends. In PBT blends with a 20 wt % CSR loading, the dispersed rubbery phases showed discernible shapes depending on the grafted GMA content, from predetermined spheres with 0.25 ± 0.05 μm diameters to their aggregates in the 2–3 μm diameter range. As a result, the interparticle spacing (τ) could be controlled from 0.25 to 4.0 μm in the PBT blends containing the fixed rubber loading. The Izod impact strengths of these samples increased significantly below τ = 0.4 μm. Additional thermal and morphological analyses strongly supported the hypothesis that the marked increase in toughness of the blends was related to less ordered lamellar formation of the PBT matrix under the confined geometry. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Compatibilization of PP/PBT and PP/PA6 blends with a new oxazoline-functionalized polypropylene

Summary Aim of this work was to study the effectiveness of a novel oxazoline-functionalized polypropylene as a compatibilizer for PP/PBT and PP/PA6 blends. This polypropylene-based compatibilizer mixes well with the polypropylene and is capable of reacting with the carboxylic and amine end groups of PBT and PA6. Significant improvements in blend toughness were achieved without reduction in strength and stiffness. These effects were related to stabilized morphology of finely dispersed minor phase well attached to the matrix. The enhanced interfacial interactions between the two phases, in particular at high PBT content were evidenced by increased melt viscosity.     

Properties of poly(butylene terephthalate) chain‐extended by epoxycyclohexyl polyhedral oligomeric silsesquioxane

Epoxycyclohexyl polyhedral oligomeric silsesquioxane (epoxy–POSS) was used to prepare a chain‐extended poly(butylene terephthalate) (PBT) with a twin‐screw extruder. The effect of epoxy–POSS on the melt flow index, mechanical properties, rheological behavior, and thermal properties of chain‐extended PBT was investigated. PBT had an intrinsic viscosity of 1.1 dL/g and a carboxy1 content of 21.6 equiv/10⁶ g, but the PBT chain‐extended with 2 wt % epoxy–POSS had an intrinsic viscosity of 1.7 dL/g and a carboxy1 content lower than 7 equiv/10⁶ g. After the addition of epoxy–POSS, the melt flow index of PBT dramatically decreased, the elongation at break increased greatly, the tensile strength increased slightly, and the thermal stability was also improved. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

聚对苯二甲酸丁二醇酯的化学扩链改性研究

以 2 ,2′ -双 ( 2 -唑啉 ) (BOZ)为扩链剂 ,对聚对苯二甲酸丁二醇酯 (PBT)进行扩链改性 ,考察了反应时间、扩链剂用量对扩链效果的影响 ,测试了扩链后PBT的热失重、力学性能和DSC。结果表明 ,BOZ的用量为 0 .44 % ,反应时间 3～ 5min ,PBT的最大扩链效率可达 72 .9% ,PBT的特性粘数从 0 .83dL/g提高到 1.2 1dL/ g ,扩链后PBT热稳定性和力学性能都得到提高。     

BIPB硫化氢化丁腈橡胶性能的研究

研究了双叔丁基过氧化异丙基苯(BIPB) 硫化剂用量对氢化丁腈橡胶混炼胶硫化特性及硫化胶力学性能、耐热性能、耐油性能及压缩永久变形性能的影响。结果表明：随着BIPB用量的增加,混炼胶的焦烧时间t10和正硫化时间t90均逐渐减小,交联效率提高;硫化胶的物理机械性能、耐热性能、耐油性能和压缩永久变形性能均逐渐提高。当BIPB用量为4份时,硫化胶的综合性能达到最优。     

强韧化PBT/PC共混物的制备与性能

采用自制的甲基丙烯酸缩水甘油酯熔融接枝丙烯腈丁二烯苯乙烯三元聚合物\[ABS-g-(GMA-co-St),AGS]为改性剂,对聚对苯二甲酸丁二醇酯（PBT）/聚碳酸酯(PC)（80/20）共混物进行改性研究。通过扫描电子显微镜、差示扫描量热仪、力学性能和流变性能测试研究了改性后共混物的性能。结果表明,随着AGS含量的增加,共混物中两相间的界面黏结增强; AGS对PBT/PC共混物具有强韧化的作用,与未添加AGS的PBT/PC共混物相比,当AGS含量为10份时,共混物的缺口冲击强度和拉伸强度分别提高了49.8 %和17.4 %;AGS的加入提高了共混物的界面强度和相容性;添加AGS能够提高共混物的结晶峰温度,起到促进晶粒生长的作用。     

Chemical transformation of nitrile to reactive oxazoline functionality on a preformed polymer

The chemical transformation of nitrile to oxazoline functionality via a soluble zinc salt-catalyzed reaction was conducted on a series of nitrile-containing copolymers, i.e., styrene–acrylonitrile (SAN) and nitrile rubbers. The results show that triad tacticity of the acrylonitrile groups is important in understanding the relative reactivity of SAN copolymers. Furthermore, the dielectric properties of the comonomer is also a prime factor in understanding the different degrees of reactivity of SAN, nitrile rubbers, and its hydrogenated analog forms. Enhanced reaction rates are noted with higher dielectric constants. © 1995 John Wiley & Sons, Inc.     

High‐performance hydrogenated nitrile butadiene rubber composites by in situ interfacial design of nanoclays

Considering industrial requests, it has become a hot issue to prepare advanced rubber composites with high strength and great toughness. Despite enhanced strength and stiffness, rubber composites suffer markedly reduced extensibility and toughness. Herein, a novel interfacial strategy is proposed to fabricate amine‐modified montmorillonite (MMT)/hydrogenated nitrile butadiene rubber composites by designing in situ ionic bond interfaces. The well‐distributed interfaces, which are composed of protonated amine groups on the MMT surfaces and electronegative methacrylic acid (MA), were constructed by adding a slurry with a small amount of MMT and MA to rubber. After the vulcanization, self‐polymerization of MA developed nanoparticles and grafting structures onto rubber chains to bond MMT by strong ion attractions. Although the crosslinking degree of rubber was reduced, the dispersion of MMT and its interfacial interactions with rubber were improved remarkably, as demonstrated by morphology observations, dynamic mechanical analysis and infrared spectra. As a result, the strength, modulus, elongation, toughness and gas barrier properties of the rubber composites were simultaneously strikingly improved relative to composites without MA modifiers. We believe that this work provides a promising methodology of fabricating high‐performance rubber composites. © 2019 Society of Chemical Industry     

Room temperature and low temperature toughness improvement in SAN/ASA blends by blending with CPE,HNBR, and BR

Styrene‐acrylonitrile copolymer (SAN)/acrylonitrile‐styrene‐acrylate terpolymer (ASA) blends (75/25, wt/wt) was toughened by blending with impact modifiers including chlorinated polyethylene (CPE), hydrogenated nitrile butadiene rubber (HNBR), and butadiene rubber (BR) and the impact property was tested at four temperatures (–30, ?15, 0, and 25 °C). The combination of CPE and HNBR was imported to toughen the SAN/ASA blends, indicating that CPE and HNBR had similar toughening effect at room temperature but HNBR exhibited a better performance at low temperature. When a little HNBR was substituted by BR, the impact strength improved dramatically with the total content of impact modifiers keeping at 30 phr. After 15 phr CPE, 10 phr HNBR and 5 phr BR were employed into blends together, the impact strength reached to a peak of 14 kJ/m² at ?30 °C while the impact strength of the blends individually toughened by 30 phr CPE or 30 phr HNBR was 5 or 12 kJ/m², respectively. The toughening mechanism showed that the low glass‐transition temperature (–108 °C) of BR and the compatibilization between BR and matrix accounted for the improvement of toughness. Simultaneously, scanning electron microscopy, dynamic mechanical analysis, flexural and tensile properties, heat distortion temperature, and Fourier transform infrared spectroscopy were measured. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45364.     

Development of biodegradable PLA/PBT nanoblends

Poly(lactic acid)/poly(butylene terephthalate) (PLA/PBT) blends with 3, 5, and 10 wt % of PBT were produced in a twin‐screw extruder, with the addition of ethylene–glycidyl methacrylate copolymer as compatibilizer. An uncompatibilized PLA/PBT blend with 5 wt % of PBT was prepared for comparison studies. The epoxy reactive groups in the compatibilizer allowed modification of the interfacial tension in the blends and reduced the PBT dimensions. The crystallinity of the blends was studied, and its influence on mechanical properties was analyzed. Tensile tests showed an increase in strain at break from 3% for neat PLA to 49% for PLA with 3 wt % PBT, while the tensile modulus dropped from 3.59 GPa to 3.35 GPa for the same samples. Izod results showed a transition from a brittle behavior of PLA to a ductile one for compatibilized blends. These results indicate that the nanometer‐size dispersed phase was effective in changing the deformation behavior of the matrix without a significant loss of modulus. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45951.     

Reactive bonding of natural rubber to metal by a nitrile–phenolic adhesive

The mechanism of adhesive bonding of rubber to metal using an interlayer of bonding agent (adhesive) is discussed with respect to various physical and chemical events such as adsorption at the metal surface, chemical crosslinking within the adhesive, interdiffusion, and formation of interpenetrating networks at the rubber–adhesive interface. An investigation on the peel strength of a natural rubber (NR)–adhesive–metal joint, made by vulcanization bonding using nitrile–phenolic adhesive containing various concentrations of toluene diisocyanate–nitrosophenol (TDI–NOP) adduct, is presented. A single‐coat adhesive, consisting of a p‐cresol phenol formaldehyde resin, nitrile rubber (NBR), and vulcanizing agents in methyl ethyl ketone solvent, was selected for the study. Considerable improvement in the peel strength was obtained by the incorporation of TDI–NOP adduct into the nitrile–phenolic adhesive. The peel strength increases as the concentration of TDI–NOP adduct in the adhesive composition increases, then levels off with a transition from interfacial failure to cohesive tearing of rubber. The peel strength improvement is believed to be attributed to the interfacial reactions between the bonding agent and natural rubber, when TDI–NOP adduct is incorporated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2597–2608, 2001     

EAA-g-PEOX对PBT/PP共混体系增容作用的研究

利用ＳＥＭ、ＤＳＣ及力学测试等分析方法,研究了增容剂ＥＡＡ－ｇ－ＰＥＯＸ及扩链剂ＰＢＯ对ＰＢＴ／ＰＰ共混物的形态结构和力学性能的影响。结果表明,ＥＡＡ－ｇ－ＰＥＯＸ明显改善了ＰＰ与ＰＢＴ的相容性,使ＰＰ较均匀地分配在基体中。     

Therban® – The High Performance Elastomer for the New Millennium

Hydrogenated nitrile rubber (Therban) was introduced in the early 80's by Bayer as an oil‐resistant elastomer for permanent exposure to temperatures between –25°C and 150°C. By specific modification of micro‐ and macrostructural features the service temperature range could be extended. The introduction of bulky side groups hinders the crystallization of methylene sequences along the polymer backbone. The inability to crystallize leads to superior dynamic‐mechanical properties at low service temperatures. High temperature properties are determined by the plateau of rubber elasticity and are mainly influenced by the network density and structure of the crosslinked polymer matrix as well as by the polymer‐filler interactions. The temperature dependence of the latter causes a decline in the reinforcement properties of filler and polymer matrix at elevated temperatures. Above 150°C a deterioration of the polymer network is observed for standard HNBR grades. This service temperature limit can be increased by ca. 10°C being equivalent to a doubling of the service life‐time by the proper use of Therban HT.     

环氧化三元乙丙橡胶对PBT结构及性能的影响

将三元乙丙橡胶（EPDM）经环氧化反应制得的环氧化三元乙丙橡胶（eEPDM）与聚对苯二甲酸丁二醇酯（PBT）熔融共混以改善PBT的缺口冲击韧性。利用红外光谱、核磁共振谱仪、动态机械热分析仪、差示扫描量热仪、扫描电子显微镜、转矩流变仪及拉伸仪与缺口冲击仪对eEPDM的结构及PBT/eEPDM的相容性、相结构、流变性能及力学性能进行了表征。结果表明,EPDM成功引入了环氧基团;PBT与eEPDM部分相容;橡胶含量低于15 %时,分散相粒径较小且分散均匀;橡胶相含量高于15 %时,分散相粒径变大且分散不均匀;添加eEPDM使得PBT的扭矩变大;eEPDM含量为5 %时,共混物的缺口冲击韧性可提高1倍。     

Polymer-Polymer Adhesion in the Presence of Compatibilizer

The influence of compatibilizers in three types of joints-natural rubber (NR)-polyethylene (PE), silicone rubber (Si)-ethylene propylene diene rubber (EPDM) and hydrogenated nitrile rubber (HNBR)-nylon has been demonstrated. The compatibilizers increase the peel strength in every case. The results are explained with the help of new approaches based on (1) strain energy density, (2) reptation scaling theory. It is observed that the diameter of the strained tip for NR-PE and Si-EPDM systems increases in the presence of compatibilizers. Also, the peel strength of the HNBR-nylon joint has a first power dependence on the interfacial thickness.