混炼工艺对SBR/BR/CB共混硫化胶性能的影响

为了研究混炼工艺对最终硫化胶性能的影响,利用HAAKE转矩流变仪对不同配比的丁苯橡胶/顺丁橡胶/炭黑进行混炼,混炼采用两种不同的混炼顺序——一种是炭黑首先与丁苯橡胶(SBR)混炼,然后加入顺丁橡胶(BR)混炼;另一种是BR与炭黑混炼之后再加入SBR进行混炼。对制得共混物进行结合胶含量、拉伸以及动态力学性能测试。结果显示,在相同配比下,炭黑首先跟份数多的富相橡胶混炼可以得到较多的结合胶,有利于体系的补强;动态力学测试结果表明硫化胶的粘弹特性受第一段混炼所用橡胶的影响较大,炭黑与柔顺性较好的BR先混炼,共混体系工艺相容性较好。     

混炼工艺对SBR/BR/CB共混硫化胶性能的影响EI北大核心

为了研究混炼工艺对最终硫化胶性能的影响,利用HAAKE转矩流变仪对不同配比的丁苯橡胶/顺丁橡胶/炭黑进行混炼,混炼采用两种不同的混炼顺序——一种是炭黑首先与丁苯橡胶(SBR)混炼,然后加入顺丁橡胶(BR)混炼;另一种是BR与炭黑混炼之后再加入SBR进行混炼。对制得共混物进行结合胶含量、拉伸以及动态力学性能测试。结果显示,在相同配比下,炭黑首先跟份数多的富相橡胶混炼可以得到较多的结合胶,有利于体系的补强;动态力学测试结果表明硫化胶的粘弹特性受第一段混炼所用橡胶的影响较大,炭黑与柔顺性较好的BR先混炼,共混体系工艺相容性较好。     

PVC/BR或SBR共混体系的研究EI

本文用Brabender塑化仪、动态粘弹谱仪、DSC分析仪和扫描电镜,研究了第三组分对聚氯乙烯/顺丁橡胶(丁苯橡胶)共混体系性能、相容性和形态结构的影响。结果表明:NBR-18是PVC/BR(SBR)的优良增容剂,可以显著地改善共混物的力学性能,在共混物中起表面活性剂的作用,促进了PVC粒子的细微化和均匀分散,增强了两相界面作用力。PVC/NBR-18/BR(SBR)综合了PVC和BR(SBR)的性能,具有良好的力学、耐老化、耐低温和阻燃性能。     

不同共混方法对不同橡胶增韧聚丙烯体系的形态结构及性能的影响

本工作采用双辊开炼机(R)和捏合锅(M)两种不同共混方法对聚丙烯(PP)分别与三元乙丙橡胶(EPT)和1,2-聚丁二烯(1,2-PB)进行共混,对所得两种共混物模压成型的试样进行了扫描电子显微镜(SEM)观察以及抗冲击强度和抗张性能的测试。结果表明,在相同时间和温度下,无论用哪种方法共混,EPT的1,2-PB对PP都有很好的增韧效果,但后者更优。从抗冲击强度和脆断面形态看不同共混方法对PP/EPT和PP/1,2-PB二种共混体系的效果是不同的,即对PP/EPT体系,以R共混优于M共混,而对PP/1,2-PB体系,则几乎没有差别。从而可以认为,共混方法对不同共混体系的效应是不同的;同方法时时间和温度等条件也是很重要的因素。     

EPDM-g-LSBR的制备及其增容EPDM/SBR并用橡胶的性能研究

采用熔融密炼接枝工艺,以三元乙丙橡胶(EPDM)为基体,低分子量液体丁苯橡胶(LSBR)为接枝物,制备了接枝聚合物EPDM-g-LSBR,研究了制备条件对接枝聚合物红外光谱和热失重行为的影响;将EPDM-g-LSBR作为相容剂用于EPDM/SBR的增容性共混,并与常用的商业化嵌段聚合物乙烯-乙酸乙烯酯(EVM)和苯乙烯-乙烯-丙烯-苯乙烯嵌段共聚物(SEPS)的增容效果进行了对比,研究了其用量对并用胶硫化特性和硫化胶力学性能的影响。结果表明,LSBR接枝到EPDM分子主链上,接枝量的变化未对产物的热降解温度造成显著影响;接枝物EPDM-g-LSBR增容后EPDM/SBR并用胶力学性能有明显改善,添加8份时,材料的拉伸强度和断裂伸长率比未添加相容剂的体系提高了24.3%和15%,邵A硬度由未添加的75.4降低到72.6。通过对混炼胶的断面进行扫描电镜分析发现EPDM-g-LSBR的加入使EPDM在SBR中的海岛分散结构消失,增加了两相的相容性。     

PSf/SPES共混相容性及其对膜形态结构和性能的影响规律

针对聚砜(PSf)和磺化聚醚砜(SPES)聚合物共混体系相容性,首先通过混合焓法计算预测并用差示扫描量热法(DSC)进行了分析.结果表明,二者为部分相容体系,且相容性随共混比的增大呈下降趋势.此外,以N,N-二甲基乙酰胺(DMAc)为溶剂,采用浸没沉淀相转化法制备出PSf/SPES共混平板超滤膜,系统研究了共混相容性对膜形态结构及性能的影响规律.结果表明,当PSf/SPES共混比小于90/10(质量比)时,聚合物共混具有较好的相容性,所制备共混膜的断面为梯度分布的海绵网络孔结构,且亲水性、表面孔孔径、孔隙率和纯水通量等均随着共混比的增大而增大.其中,当PSf/SPES=92/8时,膜的纯水通量达到1 397L/(m2·h),对牛血清蛋白(BSA)截留率为85%.随着PSf/SPES共混比进一步增加,共混体系相容性变差,膜的断面出现指状孔结构,BSA截留率显著下降.     

P34HB的4HB含量对PLLA/P34HB共混物结构和性能的影响

采用熔融共混方法制备了聚乳酸/聚(3-羟基丁酸-4-羟基丁酸酯)(PLLA/P34HB)共混物,其中P34HB的4HB摩尔含量分别为11%与17%。通过扫描电子显微镜、动态力学分析、差示扫描量热仪和力学性能测试,考察了共混物的相容性、熔融行为与力学性能。结果表明,当P34HB组分质量分数为25%以上时,共混物两相玻璃化转变温度(Tg)相互靠近,为部分相容体系,且4HB含量越少,PLLA/P34HB共混物的相容性越好。共混物中PLLA的结晶性能随P34HB含量的增加而降低,且4HB含量越大,由于较差的相容性导致P34HB对PLLA的链段运动能力影响减小,共混物中PLLA结晶性能越好。随P34HB含量的增加,共混物的强度降低,断裂伸长率升高,且4HB含量越大,共混物力学性能由于两相相容性较差而低于4HB含量较低的共混体系。     

聚合物共混对聚偏氟乙烯超滤膜结构与性能的影响

根据聚合物共混焓变、绝对黏度及凝胶点值,考察了4种聚合物(聚乙烯醇(PVA)、聚乙二醇(PEG)、聚乙烯吡咯烷酮(PVP)、聚甲基丙烯酸甲酯(PMMA))与聚偏氟乙烯(PVDF)/N,N-二甲基乙酰胺(DMAc)铸膜液体系的共混相容性。利用凝胶相转化动力学及原子力显微镜(AFM)、扫描电镜(SEM)、亲水接触角和泡点压力等检测手段,分析了水凝胶浴中4种添加剂对PVDF超滤膜成膜过程及膜结构与性能的影响。结果显示,4种添加剂与PVDF/DMAc的共混相容性顺序为PEG>PVP>PVA>PMMA。共混体系均以液液分相为主;其中PEG、PVP共混PVDF体系以瞬时分相为主,膜内部有大孔,表皮层及支撑层较为致密。PMMA和PVA共混PVDF体系有延时分相和液固分相行为,膜表面多孔、内部有大孔且亚层疏松。共混优化了PVDF超滤膜结构。PVA能有效提高膜亲水性能。     

共混聚合物/碳纳米管改性聚乳酸(PLA)复合物的研究进展

简述了聚合物改性聚乳酸(PLA)的方法,可以通过添加小分子增塑剂或可生物降解聚合物改性PLA的脆性,进一步就多元共混体系特别是可生物降解的共混聚合物中引入碳纳米管改进共混聚合物的相容性进行了介绍,对共混聚合物/碳纳米管复合材料在流变性能方面的研究进行了综述,并对共混聚合物/碳纳米管改性聚乳酸(PLA)复合物未来的发展方向提出了几点建议。     

以LiBr/C_2H_5OH/H_2O为溶剂的PVA/SF共混体系的相容性

采用LiBr/C2H5OH混合溶剂制备丝素(SF)溶液,与聚乙烯醇(PVA)水溶液进行溶液共混后得到PVA/SF共混膜,采用扫描电镜,差示扫描量热分析,红外光谱,X射线衍射等方法对共混膜进行了形态和结构表征。研究表明,相对于将PVA水溶液与SF水溶液共混得到的共混体系,此方法制备的体系中两组分的相容性得到了一定程度的提高。在SF含量较小的情况下,共混体系中几乎观察不到两相结构的存在。证明在PVA/SF体系中,SF的溶剂选择及SF的含量影响两种组分的相容性。     

Effect of grafting cellulose acetate and methylmethacrylate as compatibilizer onto NBR/SBR blends

Compatibilizer is used for improving of processability, interfacial interaction and mechanical properties of polymer blends. In this study acrylonitrile butadiene rubber (NBR) and styrene-butadiene rubber (SBR) blends were compatibilized by a graft copolymer of acrylonitrile butadiene rubber (NBR) grafted with cellulose acetate (CA) i.e. (NBR-g-CA) and acrylonitrile butadiene rubber (NBR) grafted with methylmethacrylate i.e. (NBR-g-MMA). Compatibilizers were prepared by gamma radiation induced grafting of NBR with cellulose acetate (CA) and methylmethacrylate (MMA) were added with different ratios to NBR/SBR (50/50) blend. The compatibilized blends were evaluated by rheometric characteristics, physico-mechanical properties, swelling behavior, scanning electron microscope (SEM) and thermal analysis. The results showed that, the blends with graft copolymer effect greatly on the rheological characteristics [optimum cure time (Tc₉₀), scorch time (Ts₂), and the cure rate index (CRI)]. The physico-mechanical properties of the investigated blends were enhanced by the incorporation of these graft copolymers, while the resistance to swelling in toluene became higher. SEM photographs confirm that, these compatibilizers improve the interfacial adhesion between NBR/SBR (50/50) blend which induce compatibilization in the immiscible blends. The efficiency of the compatibilizer was also evaluated by studying the thermogravimetric analysis.     

蒙脱土填充补强丁苯橡胶及对橡胶硫化特性的影响

以十八烷基三甲基溴化铵为插层处理剂改性蒙脱土。分别采用有机蒙脱土(C₁₈-MMT) 和Na-蒙脱土(Na-MMT) 填充补强丁苯橡胶, 用XRD 和TEM 对复合材料的结构进行表征。结果表明: 蒙脱土在橡胶基体中的分散取决于蒙脱土的亲油性, 亲油性越强, 蒙脱土的片层在橡胶中的分散越均匀, 完全有机化处理的蒙脱土能够被剥离成厚度为20 nm 左右的片层并均匀分散在橡胶基体中。蒙脱土的存在对橡胶的硫化反应有一定的影响, 有机蒙脱土对橡胶硫化反应有催化作用, 但不改变硫化反应的活化能; Na-蒙脱土片层阻碍了橡胶的硫化交联, 使交联反应对温度的敏感性降低, 导致表观活化能减小。有机蒙脱土填充补强丁苯橡胶, 由于提高了橡胶的交联密度, 同时有机蒙脱土具有高比表面积和滑移性, 大大提高了橡胶的机械性能, 其拉伸强度和300 %定伸应力与炭黑N330 补强橡胶相当, 而断裂伸长率较炭黑补强橡胶有大幅度的提高, 在替代炭黑作为橡胶的补强剂方面具有广泛的应用前景。      

Polyfuran,polythiophene and their blend as novel antioxidants for styrene- butadiene rubber vulcanizates

Polyfuran (PF) and polythiophene (PT) were prepared by chemical oxidation, their blend was prepared by mechanical mixing of the two polymers. The prepared polymers and their blend were characterized by viscometric polydispersity, FT-IR spectroscopy, thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). PF, PT and PF/PT blend were incorporated in Styrene–Butadiene Rubber (SBR) mixes and the rheometric characteristics were determined using an oscillating disc rheometer. The prepared polymers and their blend were evaluated as antioxidants for SBR vulcanizates. The physico-mechanical properties of SBR vulcanizates were measured before and after exposure to accelerated thermo-oxidative aging. The results revealed that the prepared polymers and their blend are efficient antioxidants for SBR vulcanizates in comparison with p-maleiyl phenylene amide polymer and polymerized 2,2,4-trimethyl-12dihydroquinoline (TMQ), the antioxidant used in industry. On the other hand, PF/PT blend showed better results than the individual polymers.     

The effect of zinc oxide–phosphate core–shell pigments on the properties of blend rubber composites

In this work the rheological, physico-mechanical, thermal and morphology studies were performed on a blend of EPDM/SBR (ethylene propylene diene monomer/styrene butadiene rubber) (50/50) loaded with a new prepared core–shell pigment based on a core of zinc oxide which presents the major component of the prepared pigment (≈90%) covered with a shell of phosphate, this shell comprises only about (≈10%). The new pigments were added in different concentration to the rubber blend and were compared to blends pigmented with commercial zinc oxide and zinc phosphate. The results showed that the new pigments exhibited better rheometric, and physico-mechanical properties. In addition, these prepared pigments showed decrease of equilibrium swelling in toluene solvent and increase in crosslink density for EPDM/SBR blend. The efficiency of prepared core–shell pigments were also evaluated by studying the surface morphology (SEM) and thermal properties TGA (thermal gravimetric analysis). The prepared pigments loading of 10 phr (parts per hundred parts of rubber) showed the optimum properties of EPDM/SBR blend than rubber loaded with higher concentration of the commercial pigments, which indicated that the new core–shell pigment is more economic with better performance than commercial zinc oxide and phosphates individually.     

Structure and properties of fibrillar silicate/SBR composites by direct blend process

Silicate attapulgite(AT)/Styrene Butadiene rubber (SBR) composites with excellent properties and low cost were first prepared from a direct blending process (including polymer melt blending and emulsion co-coagulation). The structure and properties of above composites were carefully investigated. It was found that most AT separated into dispersed units with diameters less than 100 nm in SBR by the direct blend process. However, a few dispersion units as large as 0.2–0.5 m and a clear network structure of dispersion units in SBR was observed by TEM, SEM and RPA. AT can be purified, but purified AT cannot be easily dispersed in the rubber matrix by polymer melt blending. Siliane coupling agent Si69 can improve the dispersion of AT and enhance the chemical interfacial adhesion. At the same loading, AT (pretreated with Si69) was found to have better reinforcing effect on SBR than carbon black SRF with particle size 60–100 nm and even than N330 with particle size 26–30 nm to some extent. Meanwhile, the cost of AT/SBR composites is pretty low.     

Phase separation of binary blends in polymer nanoparticles

Polymer blends in nanoparticles have been studied by transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. The TEM studies show that blend particles formed from two immiscible polymers by the miniemulsion process exhibit biphasic morphologies. The fact that no core-shell type but Janus-like structures were found indicates that the surface free energies between both polymers and the solution-water interface (including the surfactant molecules) are similar; therefore, the blend morphology and composition of the individual phases are mainly determined by the interaction between the two polymer components. Both the TEM studies and the PL experiments provide strong evidence that phase separation in these particles strictly follows the Flory-Huggins theory. This highlights the applicability of the nanoparticle approach to fabricate blend systems with well-controllable properties and to study structure-property relationships under well-defined conditions.     

EVA-g-PU/SBR/OMMT复合材料的制备与性能表征

采用熔融共混与熔融插层相结合的方法,制备了EVA-g-PU/SBR/OMMT复合材料.采用x-射线衍射仪(XRD)与透射电镜(TEM)研究了蒙脱土在聚合物基体中的分散状态,用电子万能试验机、摩擦磨损试验机测试了材料的力学性能及耐摩擦磨损性能,并通过扫面电镜分析了材料的磨损机理.结果表明,蒙脱土主要以插层型分布在聚合物基...     

Effect of expanded graphite and modified graphite flakes on the physical and thermo-mechanical properties of styrene butadiene rubber/polybutadiene rubber (SBR/BR) blends

The aim of the present research work is to develop expanded graphite (EG) and isocyanate modified graphite nanoplatelets (i-MG) filled SBR/BR blends, which can substitute natural rubber (NR) in some application areas. The present study investigated the effect of i-MG on the physical, mechanical and thermo-mechanical properties of polybutadiene rubber (BR), styrene butadiene rubber (SBR) and SBR/BR blends in the presence of carbon black (CB). Graphite sheets were modified to enhance its dispersion in the rubber matrices, which resulting in an improvement in the overall physical and mechanical properties of the rubber vulcanizates. Compounds based on 50:50 of BR and SBR with ∼3 wt% nanofillers with CB were fabricated by melt mixing. The morphology of the filled rubber blends was investigated by wide angle X-ray diffraction (WAXD) and high resolution transmission electron microscopic (HR-TEM) analyses. The intercalated and delaminated structures of the nanofiller loaded rubber blends were observed. Scanning electron microscopic (SEM) analysis of the cryo-fractured surfaces of the rubber compounds showed more rough and tortuous pathway of the fractured surfaces compared to the fractured surfaces of the only CB loaded rubber composites. Filled rubber compounds exhibit increase in the ΔS (torque difference) value, reduced scorch and cure time compared to their respective controls. Dynamic mechanical thermal analysis (DMTA) of the filled rubber compounds shows an increase in the storage modulus compared to the controls. Isocyanate modified graphite nanoplatelets (i-MG) containing rubber compounds in the presence of CB showed an increase in the mechanical, dynamic mechanical, hardness, abrasion resistance and thermal properties compared to the alone CB filled rubber vulcanizates.     

聚丙烯接枝物反应挤出增容PP/PA6共混物的形态结构

采有PP熔融接枝MAH和不饱和羧酸混合单体通过反应挤出增容PP/PA6共混物，研究了增容共混物的形态结构。SEM、TEM观察表明，接枝物能明显降低共混物的分散相尺寸，改善体系的分散状况，提高共混物两相的相容性；增容共混物的两相界面结合改善，相界面变得模糊。WAXD、DSC测试表明，用该接枝物增容后的共混物，组分的Xc下降，分散相微晶尺才减小。研究结果表明该接枝物是PP/PA6共混体系的有效增容剂。