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1.
Carlota H. F. Maurano Liliane L. Portal Ricardo Baumhardt Neto Raquel S. Mauler 《Polymer Bulletin》2001,46(6):491-498
Summary
The thermoplastic elastomers have been widely used in polymer blends to improve their mechanical properties. This work is
about the study of chemical modification of styrene-butadiene-styrene (SBS) with maleic anhydride (MA) by radical reaction.
The functionalization reaction was carried out in a mixer Haake Rheomix 600 and the torque variation was monitored during
the process. The products were characterized by Infrared Spectroscopy (FTIR) and crosslinking was evaluated by extraction.
A calibration curve was plotted to determine the functionality. The results showed that it is possible to accomplish the functionalization
reaction avoiding the crosslinking.
Received: 26 February 2001/Revised version: 25 June 2001/Accepted: 25 June 2001 相似文献
2.
Measurements were made of linear viscoelastic properties and nonlinear stress-strain properties of phase-separated styrene-butadiene-styrene (SBS) copolymers and their blends with several homopolymer polystyrenes (PS) and one random copolymer (SBR). Torsion pendulum testing yielded shear moduli G′, G″, and Rheovibron experiments produced tensile moduli E′, E″, over a 220°K range of temperature, both at low frequencies. For pure copolymers and their PS blends, G′ and E′ correlated quite well with the total PS content, but G″ and E″ were more sensitive to how the additive was distributed. Results suggest that a PS additive whose molecular weight (M) is less than that of the copolymer PS-block (Ms) causes expansion of both the interphase and the homogeneous PS-rich phase, while an additive with M > Ms mixes less well with these phases (probably forming separate domains of pure PS) and is less effective in enhancing the linear moduli. The blending with SBB produced reduction in G′ but a broad midrange peak in G″, suggesting that SBR was localized almost entirely within an expanded interphase. Tensile stress-strain data were obtained with an Material Testing System at room temperature. For PS blends, properties did not correlate well with the total PS content, the blends being always weaker than the SBS of the same overall composition. The amount of set also increased with PS content in the blends. Cyclic tests to increasing strain showed progressive structural alterations (as for the host SBS), with blend behavior resembling host properties more closely with each new cycle. When SBR was the additive, amounts as small as 1 percent reduced the curves by 15 percent. The yield stress was eliminated entirely with an addition of 10 percent SBR, but for all cases the set was the same. Results are discussed in terms of interphase force barriers to chain flow. 相似文献
3.
通过测定交联体系凝胶含量的方法,考察了在紫外光辐照下,苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)进行光化学交联反应的影响因素,并研究了SBS/有机蒙脱土(OMMT)复合材料的光化学交联反应。结果表明,在N2气氛下,提高辐照温度有利于增加SBS交联体系的凝胶含量,且凝胶速率增长较快,辐照温度宜为130℃;与空气气氛比较,N2气氛对SBS的交联反应更有利;与引发剂二苯甲酮相比,安息香二甲醚(BDK)的引发效率高,BDK的最佳质量分数为1%;交联剂宜为异氰尿酸三烯丙酯,当其质量分数为1%时,SBS交联体系的凝胶含量达到最大值;与SBS交联体系相比,SBS/OMMT复合材料交联体系的凝胶速率明显下降。 相似文献
4.
Non-bonded and covalently bonded organic-inorganic hybrids materials, SBS-NO2/SiO2, SBS-NH2/SiO2 and SBS-Si(OCH3)3/SiO2, were prepared by the sol-gel process using tetraethoxysilane (TEOS) in presence of modified SBS, SBS-NO2, SBS-NH2 and SBS-Si(OCH3)3, respectively, with HCl as a catalyst. The modified SBS was prepared without damage its molecular weight and chemical structure,
which was identified by the means of FTIR spectroscopy, elementary analysis, and Wijs titration. The interfacial force and
the properties such as hemical resistance, elongation, thermal stability, and dynamic mechanical properties of the hybrids
were investigated in detail. 相似文献
5.
The excimer fluorescence of a triblock copolymer, styrene-butadiene-styrene (SBS) containing 48 wt% polystyrene was used to investigate its miscibility with poly(vinyl methyl ether) (PVME). The excimer-to-monomer emission intensity ratio IM/IE can be used as a sensitive probe to determine the miscibility level in SBS/PVME blends: IM/IE is a function of PVME concentration, and reaches a maximum when the blend contains 60% PVME. The cloud point curve determined by light scattering shows a pseudo upper critical solution temperature diagram, which can be attributed to the effect of PB segments in SBS. The thermally induced phase separation of SBS/PVME blends can be observed by measuring IM/IE, and the phase dissolution process was followed by measuring IM/IE at different times. 相似文献
6.
Hideko T. Oyama 《Polymer》2009,50(3):747-276
Poly(lactic acid) (PLA) is well known as a biocompatible, bioresorbable, and biodegradable polymer superior to petrochemical polymers from the standpoint of total energy consumption and life-cycle CO2 emission, since it can be obtained from natural sources. However, the brittleness of PLA is a big drawback for its wide application. Although many studies have been carried out modifying PLA, there is very limited work on reactive blending of PLA. This study demonstrates a dramatic improvement in the mechanical characteristics of PLA by its reactive blending with poly(ethylene-glycidyl methacrylate) (EGMA). It is shown that the interfacial reaction between the component polymers contributes to the formation of super-tough PLA materials, superior to benchmark acrylonitrile-butadiene-styrene (ABS) resins. The novel material highlights the importance of interface control in the preparation of multi-component materials. 相似文献
7.
Cristina D. Cordella Nilo S. M. Cardozo Ricardo Baumhardt Neto Raquel S. Mauler 《应用聚合物科学杂志》2003,87(13):2074-2079
A styrene–butadiene–styrene triblock copolymer (SBS) was functionalized with glycidyl methacrylate (GMA). Grafting reactions were carried out in an internal mixer at 170°C, using dicumyl peroxide (DCP) as an initiator. The effect of three variables, % GMA, % DCP, and reaction time, on grafting were studied using a factorial design to analyze the experimental data. GMA was grafted onto SBS and its incorporation increased with the % GMA added. The factors levels studied indicated that was an optimum % DCP point about 0.1% w/w to achieve the best incorporation and conversion values. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2074–2079, 2003 相似文献
8.
9.
以马来酸酐为单体、过氧化物为引发剂,采用熔融挤出法制备了乙烯-醋酸乙烯酯共聚物接枝马来酸酐(EVA-g-MAH)。重点讨论了不同型号的EVA、过氧化物引发剂品种及用量、单体MAH用量和加工工艺条件等因素时接枝反应的影响。通过化学滴定法和傅立叶红外光谱法(FTlR)证实部分马来酸酐确实以化学键连接到EVA分子链上。与聚乙烯(PE)、聚丙烯(PP)相比,EVA中由于含有醋酸乙烯(VA)基团,极性较大,与MAH的相客性较好,因而在相同的条件下接枝效率也更大;而且VA含量越大,越有利于接枝反应。比较不同的过氧化物引发剂BPO和DCP。发现DCP的引发效果更好。实验结果还表明,在EVA进行接枝反应的同时存在着交联反应,引发剂DCP的用量不宜过高,为得到接枝率适中,交联度很小的接枝产物,还要选择合适的MAH与DCP的用量。 相似文献
10.
以乙烯-马来酸酐共聚物(ZeMac)作为反应性相容剂,利用熔融纺丝法制备了聚碳酸亚丙酯(PPC)-聚乳酸(PLA)共混纤维。通过傅里叶变换红外光谱仪、热重分析仪、差示扫描量热分析仪、纤维强伸度仪等分别研究了共混纤维的分子结构、热稳定性、相容性及力学性能。结果表明:PLA的引入较大地提高了PPC的力学性能,加入少量的ZeMac可以有效地改善PPC的热稳定性,同时也能够提高共混体系的相容性。当PPC-PLA与PPC-PLA-ZeMac体系组分质量比分别为70/30和70/30/0.7时,其抗拉强度分别为11.23 MPa和20.83 MPa,较未改性的PPC分别提高了6.5倍和12.1倍,同时还能保持较高的断裂伸长率。该项研究为完全可生物降解PPC熔融共混纤维的工业化提供了可能性。 相似文献
11.
Reactive blending as a tool for obtaining poly(ethylene terephthalate)-based engineering materials with tailored properties 总被引:1,自引:0,他引:1
Siyamak Safapour Finizia Auriemma Odda Ruiz de Ballesteros Rocco Di Girolamo Ali Khosroshahi 《Polymer》2010,51(19):4340-4350
The structure and properties of blends of poly(ethylene terephthalate) (PET) with poly(trimethylene terephthalate) (PTT) at PTT concentration ≤30 wt.%, obtained with three different methods: from solution, melt extrusion, and direct spinning, are investigated. Relationships between the method of preparation and properties of blends are established. All blends show glass transition temperature at values determined by composition, and crystallization properties also dependent on the preparation method. Blends obtained from solution show separated melting of components. For blends obtained from the melt only PET crystallizes. The melting temperature decreases with the residence time of the melt at high temperatures, due to occurrence of ester exchange reactions. It is shown that reactive blending of PET/PTT mixtures occurring during preparation is a versatile route for obtainment of engineering materials with good mechanical properties, high crystallinity, glass transition temperature lower than that of PET, and melting temperature that may be controlled by the processing conditions. 相似文献
12.
Poly(butylene terephthalate) (PBT), a thermoplastic polyester, was melt blended with acrylonitrile-butadiene-styrene (ABS) terpolymer using styrene-maleic anhydride (SMA) as the compatibilizer. The PBT : ABS ratio was fixed at 70 : 30 by weight and weight percent (wt %) of SMA was varied as 2.5, 5, and 7.5. The effect of variation of the SMA percent in the blend was studied by calculating and comparing the theoretical tensile strength values with the experimental ones. The adhesive strength (σ) and the interaction parameter (I) were also determined. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 1485–1487, 1997 相似文献
13.
Yasuhisa Tsukahara Hanafi Ismail Kazunari Takenaka Norihisa Yoshimoto Kyoji Kaeriyama 《Polymer International》1999,48(5):398-405
End-carboxylated telechelic poly(ε-caprolactone)s (XPCLs) with different molecular weights were blended into a triblock copolymer of styrene–(epoxidized butadiene)–styrene (ESBS) to investigate the curing behaviour and the mechanical properties of the XPCL/ESBS binary reactive blend. It was found that the time–torque cure curve showed a significant torque increase after a very short induction period, in which the degree of the torque increase depended on the molecular weight of XPCL. This indicates that substantial crosslinking reaction takes place between the XPCLs and the epoxidized polybutadiene of the ESBS. Stress–strain curves of the blends after cure depended on the molecular weight of XPCL and the blend ratio. The XPCL/ESBS blends had sufficient thermal stability to show elastomeric behaviour at elevated temperature above the glass transition of the styrene domains of ESBS because of formation of crosslinking points between unlike polymer components by the reactive blending. © 1999 Society of Chemical Industry 相似文献
14.
A new dihydroxy monomer, (E)‐1‐(4‐(4‐(4‐hydroxybenzylidene)thiocarbamoylaminobenzyl)phenyl)‐3‐(4‐hydroxybenzylidene)thiourea, was synthesized and polymerized with thiophene‐2,5‐dicarbonyl/terephthaloyl chloride. The structural characterization of the resulting polymers was carried out using spectral techniques (Fourier transform infrared and 1H NMR) along with a physical property investigation. Novel polyesters are readily soluble in various amide solvents and possess high molar mass of 112 × 103–133 × 103 g mol?1. The thermal stability was determined via 10% weight loss to be in the range 519–523 °C and the glass transition temperature was 286–289 °C. Electrically conducting poly(azomethine‐ester)‐blend‐polyaniline blends were prepared using mash‐blending and melt‐blending techniques. Materials obtained using the conventional melt‐blending approach generated an efficient conductive network compared with those produced by mash blending. Field emission scanning electron microscopy revealed a nano‐blend morphology for the melt‐blended system owing to increased physical interactions (hydrogen bonding and π–π stacking) between the two constituent polymers. Miscible blends of thiophene‐based poly(azomethine‐ester)‐blend‐polyaniline had superior conductivity (1.6–2.5 S cm?1) and thermal stability (T10 = 507 °C) even at low polyaniline concentration relative to reported thiophene/azomethine/polyaniline‐based structures. The new thermally stable and conducting nano‐blends could be candidates for various applications including optoelectronic devices. © 2012 Society of Chemical Industry 相似文献
15.
A series of amphiphilic poly(2‐hydroxyethyl methacrylate)‐b‐polydimethylsiloxane‐b‐poly(2‐hydroxyethyl methacrylate) (pHEMA‐b‐PDMS‐b‐pHEMA) (A‐B‐A) triblock copolymers were synthesized from three different carbinol‐terminated polydimethylsiloxanes with varying molecular weight. A carbinol‐terminated polydimethylsiloxane was modified with 2‐bromoisobutyryl bromide to obtain a macroinitiator. The block copolymers were characterized by NMR, GPC, and dynamic light scattering (DLS). Reverse micelles of a copolymer were formed in mixture of benzene/methanol solution which served as nanoreactors for the synthesis of magnesium fluoride (MgF2) nanoparticles. The MgF2 was prepared via chemical precipitation using magnesium chloride and potassium fluoride as reactants. The MgF2‐triblock copolymer composites were synthesized as a function of MgF2–weight ratio (0.5, 5, and 10 wt%) in copolymer. The MgF2 colloids were dissolved in three organic solvents: methanol, isopropanol, and tetrahydrofuran. The polymer nanoparticles were characterized by DLS, transmission electron microscopy, thermogravimetric analysis, and X‐ray diffraction (XRD) analysis. The formation of MgF2 crystals was observed by XRD. Particle size and particle size distribution showed significant changes in different solvents. The thermal stability of MgF2 colloids increased as the amount of nanoparticle increased in polymeric matrix. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
16.
《Journal of the European Ceramic Society》2023,43(6):2295-2305
For the first time, dense continuous carbon fiber (Cf) reinforced (TiZrHfNbTa)C high-entropy ceramic (Cf/HEC) composites were rapidly prepared via in-situ reactive melt infiltration (RMI). A TiZrHfNbTa high-entropy alloy served as the cation source and carbon in Cf reinforced carbon matrix (Cf/C) preforms served as the anion source, and a (TiZrHfNbTa)C high-entropy ceramic phase with a near equimolar ratio was successfully formed. The results revealed that most of the TiZrHfNbTa high-entropy alloy reacted with the carbon matrix, and the harvested Cf/HEC composites exhibited an excellent bending strength (612.6 MPa) and low ablation rates. High reaction rates caused by ultra-high temperature and homogeneous distribution of elements in the high-entropy TiZrHfNbTa alloy significantly reduced the difference in reactivity with C among Ti, Zr, Hf, Nb, and Ta are considered to be the reasons for successful formation of (TiZrHfNbTa)C high-entropy ceramic with a near equimolar ratio in Cf/HEC composites. 相似文献
17.
Katsumasa Suzuki Yoshihiro Saito Yoshikazu Tokuoka Masahiko Abe Takatoshi Sato 《Journal of the American Oil Chemists' Society》1997,74(1):55-59
The volatility behavior of perfume compounds in poly(ethylene oxide)/poly(propylene oxide)/poly(ethylene oxide) copolymer
was investigated by means of dynamic and static headspace analyses. Suppression of the volatility of perfume compounds by
EO105PO27EO105 copolymer was markedly greater than by polyethyleneglycol. This suppressive effect may be due to micelle and gel formation
of EO105PO27EO105 copolymer. EO105PO27EO105 copolymer is expected to be useful as a novel sustained-release carrier that maintains constant release rates for the volatility
of perfume compounds over a wide temperature range. 相似文献
18.
Organoclays containing various amounts of stearic acid (SA) were synthesized, and clay/polystyrene‐block‐polybutadiene‐block‐polystyrene triblock copolymer (SBS) intercalated nanocomposites were prepared using organoclays containing SA by melt‐blending. Montmorillonite was the clay used, and both stearylamine and SA were used as surface modifiers. The amount of SA added was 0, 20, 50 and 100% of the cation‐exchange capacity (CEC). In this study, the effects of SA on the microstructure and mechanical properties of the clay/SBS nanocomposites were investigated. In clay/SBS with 100% CEC of SA, although no exfoliation of the clay occurred, the stacked clay layers were uniformly dispersed at the nanometer level (100–800 nm) without agglomeration. Clay/SBSs containing SA exhibited superior mechanical properties compared to clay/SBS without SA. It was found that SA effectively improved the clay dispersion in the SBS matrix and the mechanical properties of the clay/SBSs. Copyright © 2006 Society of Chemical Industry 相似文献
19.
Ordered mesoporous materials, due to its potential applications in catalysis, separation technologies, and nano-science have attracted much attention in the past few years. In this work, a novel PEO-based composite polymer electrolyte by using organic-inorganic hybrid EO20PO70EO20 @ mesoporous silica (P123 @ SBA-15) as the filler has been developed. The interactions between P123 @ SBA-15 hybrid and PEO chains are studied by X-ray diffraction (XRD), differential scanning calorimeter (DSC), and FT-IR techniques. The effects of P123 @ SBA-15 on the electrochemical properties of the PEO-based electrolyte, such as ionic conductivity, lithium ion transference number are studied by electrochemical ac impedance spectroscopy and steady-state current method. The experiment results show that P123 @ SBA-15 can enhance the ionic conductivity and increase the lithium ion transference number of PEO-based electrolyte, which are induced by the special topology structure of P123 in P123 @ SBA-15 hybrid, at the same time. The excellent lithium transport properties and broad electrochemical stability window suggesting that PEO-LiClO4/P123 @ SBA-15 composite polymer electrolyte can be used as candidate electrolyte materials for lithium polymer batteries. 相似文献
20.
Tetrafluoroethylene–perfluoroalkyl vinylether copolymer (PFA) sheet surfaces were modified with argon, helium, oxygen, and hydrogen plasmas. How the four plasmas modified the PFA sheet surfaces was investigated. All plasmas modified the PFA surfaces and at the same time initiated degradation of the PFA polymer chains. The balance between modification and degradation was strongly influenced by the magnitude of the discharge current in the plasmas. Efficiency of the plasmas in modification was hydrogen plasma > oxygen plasma > argon plasma > helium plasma. The modification involved defluorination of CF2 carbons into CHF and CH2 carbons and oxidation into O? CH2, O? CHF, and O? CF2 groups. The surface‐modification technique (a combination of hydrogen plasma treatment and silane coupling treatment) proposed in this study was applied for copper metallization of the PFA surface. The utility of the technique was confirmed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1087–1097, 2002 相似文献