Effect of styrene–isoprene–styrene,styrene–butadiene–styrene,and styrene–butadiene–rubber on the mechanical,thermal, rheological,and morphological properties of polypropylene/polystyrene blends

The mechanical, thermal, rheological, and morphological properties of polypropylene (PP)/polystyrene (PS) blends compatibilized with styrene–isoprene–styrene (SIS), styrene–butadiene–styrene (SBS), and styrene–butadiene–rubber (SBR) were studied. The incompatible PP and PS phases were effectively dispersed by the addition of SIS, SBS, and SBR as compatibilizers. The PP/PS blends were mechanically evaluated in terms of the impact strength, ductility, and tensile yield stress to determine the influence of the compatibilizers on the performance properties of these materials. SIS‐ and SBS‐compatibilized blends showed significantly improved impact strength and ductility in comparison with SBR‐compatibilized blends over the entire range of compatibilizer concentrations. Differential scanning calorimetry indicated compatibility between the components upon the addition of SIS, SBS, and SBR by the appearance of shifts in the melt peak of PP toward the melting range of PS. The melt viscosity and storage modulus of the blends depended on the composition, type, and amount of compatibilizer. Scanning electron microscopy images confirmed the compatibility between the PP and PS components in the presence of SIS, SBS, and SBR by showing finer phase domains. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 266–277, 2003     

PSA performances and viscoelastic properties of SIS‐based PSA blends with H‐DCPD tackifiers

Hotmelt pressure sensitive adhesives (PSAs) usually contain styrenic block copolymers like styrene–isoprene–styrene (SIS), SBS, SEBS, tackifier, oil, and additives. These block copolymers individually reveal no tack. Therefore, a tackifier is a low molecular weight material with high glass transition temperature (T_g), and imparts the tacky property to PSA. The SIS block copolymer with different diblocks was blended with hydrogenated dicyclopentadiene (H‐DCPD tackifier), which has three kinds of T_g. PSA performance was evaluated by probe tack, peel strength, and shear adhesion failure temperature. PSA is a viscoelastic material, so that its performance is significantly related to the viscoelastic properties of PSAs. We tested the viscoelastic properties by dynamic mechanical analysis and the thermal properties by differential scanning calorimeter to investigate the relation between viscoelastic properties and PSA performance. © 2006 Wiley Periodicals, Inc. J Appl PolymSci 102: 2839–2846, 2006     

Morphology of pyrolyzed polystyrene–isoprene–styrene and polystyrene–butadiene–styrene block copolymers

The surface morphology of thermooxidative‐degraded polystyrene–isoprene–styrene (SIS) and polystyrene–butadiene–styrene (SBS) thermoplastic block copolymers were studied by scanning electron microscopy. Surface changes caused by heating the samples in a pyrolizer for 15 and 30 min were presented in different micrographs. The morphological changes occurring due to the formation of polar groups and their crossing linking during the thermooxidative degradation are discussed. Morphological study of these thermally degraded polymer samples show very good correlation with the thermodegradation results. The rate of thermodegradation is fast in case of SBS compared with SIS block copolymer. ©2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Composition and Performance of Styrene-Isoprene-Styrene (SIS) and Styrene-Butadiene-Styrene (SBS) Hot Melt Pressure Sensitive Adhesives

Styrenic block copolymers are widely used in HMPSA formulations, with tackifier resins and oil plasticizer. Although most commercial formulations are based on SIS, mixtures of SIS and SBS are also used to reduce cost. However, the use of SBS is restricted because it generally leads to decrease in tack. In this work, pure SIS and SBS and a SIS/SBS mixture were used in formulations with aliphatic, aromatic, aliphatic hydrogenated, and aliphatic-aromatic copolymer resins, at three different oil contents, according to a 3^3–1 factorial design. Interaction effects among the components were evaluated, showing a strong dependence of the HMPSA final properties on the combination of resin/rubber used. It was found that a blend of aliphatic and aromatic resins is the best tackifier for SIS, while for SBS the best choice is an aromatic-aliphatic copolymer. These results were explained in terms of specific compatibility, which was correlated to the polarizability of the material.     

Morphology of pyrolysed polystyrene–isoprene–styrene and polystyrene–butadiene–styrene block copolymers

The surface morphology of thermooxidative degraded polystyrene–isoprene–styrene (SIS) and polystyrene–butadiene–styrene (SBS) thermoplastic block copolymers was studied by scanning electron microscopy. Surface changes caused by heating the samples in a pyrolyzer for 15 and 30 min were presented in different micrographs. The morphological changes occurring due to the formation of polar groups and their crosslinking during the thermooxidative degradation are discussed. Morphological study of these thermally degraded polymer samples shows very good correlation with the thermodegradation results. The rate of thermodegradation is fast in case of SBS when compared with SIS block copolymer. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 2549–2553, 2006     

Performance of tocopherols as antioxidants in ABS

Mixed tocopherols, γ‐tocopherol, and δ‐tocopherol were evaluated for antioxidant performance in acrylonitrile–butadiene–styrene by using oxidative induction time as the response. Three commonly used phenolic antioxidants and vitamin E (α‐tocopherol) were used as controls. Mixed tocopherols were found to have a greater antioxidant effect than the hindered phenolic antioxidants or vitamin E in acrylonitrile–butadiene–styrene. γ‐tocopherol was found to be primarily responsible for the improved performance of mixed tocopherols. J. VINYL. ADDIT. TECHNOL. 12:66–72, 2006. © 2006 Society of Plastics Engineers     

用SIS及SBS制备热熔压敏胶的工艺研究

本文探讨了用SIS和SBS制备热熔压敏胶的工艺条件及最佳组成问题,实验表明,当SBS与SIS用量为1：1时,其产品性能与SIS热坟敏胶性能相当,选用R100或聚萜烯树脂作为增粘剂,产品的粘接力较大,增塑剂的用量及材料的组成对产品的性能也有一定的影响。     

标签用热塑性弹性体SDS热熔压敏胶性能的探讨

为改善热熔压敏胶黏制品一不干胶标签的黏附性能,并进一步降低生产成本,研究了以苯乙烯系热塑性弹性体SDS（包括SBS、SIS）为基本树脂合成的热熔压敏胶的性能,并讨论了增黏树脂及软化剂的种类和用量对标签用热熔压敏胶性能的影响。结果显示,在以SIS为主体材料的热熔压敏胶中,添加价格较低的SBS,当其配比在15／85～25／75之间,热熔压敏胶的性能有所提高;而增黏树脂及软化剂的优化,对胶黏剂的综合性能有着不可忽视的作用。     

Measurement of crosslinking degree for electron beam irradiated block copolymers

The molecular weight between crosslinking junctions (Mc) of styrene-butadiene-styrene (SBS) and that of styrene-isoprene-styrene (SIS) irradiated by electron beams (5 Mrad to 100 Mrad) was measured by dynamic modulus, glass transition temperature, static modulus, and swelling. The change in dynamic modulus at low temperature was smaller than that at high temperature in both SBS and SIS. The shift of Tg to higher temperature was observed in both SBS, and SIS systems except for 100 Mrad of SIS. Both dynamic and static moduli increased with irradiation doses, however, the change of static modulus was smaller than that of dynamic one. Those mechanical measurements were compared with the swelling measurements and discussed.     

热塑性弹性体SIS和SBS的热降解行为研究

利用热重法研究了SBS（苯乙烯／丁二烯／苯乙烯热塑性弹性体）和SIS（苯乙烯／异戊二烯／苯乙烯热塑性弹性体）在N2气氛下以不同升温速率β时的热降解过程及动力学。结果表明，SIS的热降解过程分3步完成，SBS的热降解分2步完成，后者的热稳定性高于前者；SIS的热降解反应活化能为193．2kJ／mol，SBS的热降解属随机成核和随后生长过程控制机理，热降解反应的活化能为303．5kJ／mol。     

SIS/SBS/PP共混改性的研究

研究了新型聚丙烯(PP)合金材料的配方、制备、工艺及性能。分别讨论了不同用量的三元乙丙橡胶 (EPDM)、苯乙烯与异戊二烯嵌段共聚物(SIS)及苯乙烯与丁二烯嵌段共聚物(SBS)与PP组成的二元和三元共混体系对材料力学性能的影响。结果表明:SIS为PP较好的增韧剂,PP／SIS/SBS三元共混体系具有较好的协同效应,在某种程度上可以代替EPDM改性PP,共混改性后拉伸强度、扯断伸长率等性能优良。     

嵌段共聚物SBS／SIS的接枝改性研究

以SBS和SIS为基材,采用不同橡胶胶种、丙烯酸及其酯类单体进行接枝共聚合成胶粘剂。研究了 CSM(氯磺化聚乙烯)、A-90(氯丁橡胶)、NR(丁腈)等橡胶胶种对SBS／SIS与AA／BA／MMA／GDMA进行化学改性的影响,同时还探讨了N-MAM(N-羟甲基丙烯酰胺)、GDMA(二甲基丙烯酸乙二醇酯)、TMPTMA(三羟甲基丙烷甲基丙烯酸酯)、MAH(顺丁烯二酸酐)、VAc(醋酸乙烯)等单体对SBS／SIS、丁腈橡胶、氯丁橡胶为接枝母体进行化学改性的效果。结果表明:以SBS／SIS为基材,以氯丁橡胶(A-90)为接枝母体,用AA／BA／ MMA／环氧丙烯酸酯／MAH／N-MAM／GDMA／TMPTMA／VAc混合单体进行接枝改性制得的胶粘剂对极性材料帆布的粘附力较强;以SBS／SIS为复合基材,以丁腈橡胶为接枝母体,用AA／BA／MMA／TMPTMA混合单体接枝改性制得的胶粘剂对非极性材料PP片的粘接强度较高。     

Plasticization of nano‐CaCO3 in polystyrene/nano‐CaCO3 composites

The shear rheological properties of polystyrene (PS)/nano‐CaCO₃ composites were studied to determine the plasticization of nano‐CaCO₃ to PS. The composites were prepared by melt extrusion. A poly(styrene–butadiene–styrene) triblock copolymer (SBS), a poly(styrene–isoprene–styrene) triblock copolymer (SIS), SBS‐grafted maleic anhydride (SBS–MAH), and SIS‐grafted maleic anhydride were used as modifiers or compatibilizers. Because of the weak interaction between CaCO₃ and the PS matrix, the composites with 1 and 3 phr CaCO₃ loadings exhibited apparently higher melt shear rates under the same shear stress with respect to the matrix polymer. The storage moduli for the composites increased with low CaCO₃ concentrations. The results showed that CaCO₃ had some effects on the compatibility of PS/SBS (or SBS–MAH)/CaCO₃ composites, in which SBS could effectively retard the movement of PS chain segments. The improvement of compatibility, due to the chemical interaction between CaCO₃ and the grafted maleic anhydride, had obvious effects on the rheological behavior of the composites, the melt shear rate of the composites decreased greatly, and the results showed that nano‐CaCO₃ could plasticize the PS matrix to some extent. Rheological methods provided an indirect but useful characterization of the composite structure. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

SIS/SBS压敏胶改性方法

综述了SIS/SBS压敏胶的改性方法,分析了各种改性的原理,主要介绍了在弹性体上引入极性基团或链段的改性方法,添加其它类型的胶粘剂或添加剂来对压敏胶进行共混改性,以及利用电子束或紫外光进行化学交联实现对SIS/SBS压敏胶改性,并对比了这些改性方法的改性效果。     

环氧化SDS型热熔压敏胶的制备及粘接性能研究

采用苯乙烯-丁二烯-苯乙烯(SBS)和苯乙烯-异戊二烯-苯乙烯(SIS)嵌段共聚物,并配合极性的环氧化SBS(ESBS)和环氧化SIS(ESIS)作为基体材料,制备了环氧化SDS(苯乙烯系热塑性弹性体)型热熔压敏胶。研究了ESBS和ESIS用量对压敏胶的初粘力、持粘力和在不同极性底材上剥离强度的影响。结果表明,随着ESBS和ESIS用量的增加,压敏胶的初粘力和持粘力下降,在聚乙烯(PE)上的剥离强度下降,但在聚氯乙烯(PVC)和不锈钢上的剥离强度先增加后下降。当ESBS和ESIS的质量份数均为20份时,压敏胶的初粘力和持粘力分别为23#和43.6 h,在PVC和不锈钢底材上的剥离强度分别达到0.82 N/mm和1.10 N/mm。     

The effect of interfacial adhesion on the impact strength of immiscible PP/PETG blends compatibilized with triblock copolymers

In this work, recycled Poly(ethylene glycol-co-cyclohexane-1,4-dimethanol terephthalate) plastic (PETG) was used to enhance the properties and lower the cost of polypropylene(PP). In order to adjust the interfacial adhesion, three triblock copolymers having the same styrene block at two ends but different block in the middle, were used a the compatibilizers, namely, styrene–ethylene/butylene–styrene (SEBS), styrene–butadiene–styrene (SBS), styrene–isoprene–styrene (SIS). The ratio of PP to PETG was fixed at 70/30 and the relationship between interfacial adhesion and mechanical properties was investigated. The addition of SIS caused a considerable increase in Izod impact toughness, but only slightly improved toughness was observed for blends compatibilized with SEBS. The effect of SBS on improving the impact toughness lied in between that of SIS and SEBS. SEM micrographs showed that PETG forms a fibrillar-like structure for all the uncompatibilized and compatibilized blends, and the blends compatibilized with SBS have smallest domain size, the blends compatibilized with SEBS have largest domain size, while the ones compatibilized with SIS show a moderate domain size. Results from melt rheometry and SEM observation together with work of interfacial adhesion, indicated a strongest interfacial adhesion in blends compatibilized with SBS, poorest in blends compatibilized with SEBS, and moderate in blends compatibilized with SIS. It is very interesting to found that the much improved impact strength was not observed in the blends with the strongest interfacial adhesion but achieved in the blend with moderate interfacial adhesion. Investigation on the impact fractured surface revealed an easier debonding of fibril from matrix and consequently drawn out of matrix in blends compatibilized by SIS with moderate interfacial adhesion, which was considered as the main reason for the much improved impact toughness in this system.     

Singlet oxygen generation and adhesive loss in stimuli‐responsive,fullerene‐polymer blends,containing polystyrene‐block‐polybutadiene‐block‐polystyrene and polystyrene‐block‐polyisoprene‐block‐polystyrene rubber‐based adhesives

The adhesive properties, as measured by bulk tack and peel strength analysis, were found to decrease in polystyrene‐block‐polybutadiene‐block‐polystyrene (SBS) and polystyrene‐block‐polyisoprene‐block‐polystyrene (SIS) PSA films containing common singlet oxygen generators, acridine, rose bengal, and C₆₀ fullerene, when irradiated with a tungsten halogen light in air. The addition of the singlet oxygen quencher, β‐carotene, to the C₆₀ fullerene samples was found to significantly deter the rate of adhesive loss in the fullerene‐SBS and ‐SIS PSA nanocomposites. The presence of oxygen was essential to the mechanism of adhesive loss and, in combination with the effects of singlet oxygen generators and a singlet oxygen scavenger, strongly supports a singlet‐oxygen mediated process. FTIR investigations of fullerene‐SBS and ‐SIS systems suggest the initial formation of peroxides which, upon further irradiation, lead to the generation of carbonyl‐containing compounds of a ketonic type after crosslinking. Rates of SBS and SIS C‐H abstraction were comparable and found to decrease when the high‐pressure, mercury xenon irradiation source was filtered to allow only light of λ > 390 nm. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

SBS/SIS嵌段共聚物的有机硅改性研究

嵌段共聚物SBS／SIS由于结构中有不饱和键而存在耐热、耐老化性较差的问题,采用不同单体和有机硅对嵌段共聚物进行复合改性,并通过测试所制胶黏剂的软化点、剥离强度、硬度、接枝率和黏度等各项指标评价其改性效果。由于加入WD-20改性后生成具有Si—O键的SBS／SIS聚合物,对所连烃基起屏蔽作用。提高了胶的热氧化稳定性。同时生成交联度更加稳定的Si-O-Si键可防止主链的断裂降解。从而使胶的耐热性能有所提高。实验结果证实了对嵌段共聚物SBS／SIS进行有机硅复合改性后,其耐热、耐老化性能得到明显提高,从而拓宽了其使用范围。     

苯乙烯类热塑性弹性体对IR／CR的增容作用

采用相差显微镜及Ｍｏｏｎｙ－Ｒｉｖｌｉｎ方程中的２Ｃ１和２Ｃ２等方法，研究了少量ＳＩＳ，ＳＢＳ，α－甲基苯乙烯和丁二烯的三嵌段共聚物（ＭＳＢＭＳ）对ＩＲ／ＣＲ共混物相态结构、交联行为和力学性能的影响。结果表明，加入ＳＩＳ，ＳＢＳ，ＭＳＢＭＳ厅明显降低分散相尺寸，使体系分布均匀，提高了硫化胶的交联密度和拉伸强度。降低节体系煌内部损耗。对ＩＲ／ＣＲ共混物的增容效果，以ＳＩＳ为最好，ＳＢＳ次之，ＭＳＢＭ     

PS热塑弹性体环氧化对胶粘剂性能的影响

通过对苯乙烯类热塑性弹体ＳＢＳ、ＳＩＳ、ＥＳＢＳ、ＥＳＩＳ的溶度参数进行估算入手，从理论上讨论了环氧化对苯乙烯热塑性弹性体胶粘剂的本体强度，增粘剂的互溶行为的影响，通过胶粘剂性能的测试探讨了ＳＢＳ环氧化后对胶接性能的影响。