Synthesis of polystyrene-styrene/butadiene diblock copolymers via reversible addition-fragmentation chain transfer miniemulsion polymerization

Polystyrene-styrene/butadiene diblock copolymers were synthesized via reversible addition-fragmentation chain transfer （RAFT） miniemulsion polymerization.During the polymerization process,the molecular weight distribution was narrow and the numerical molecular weight of the copolymers increased with increasing conversion of monomers,which was close to the theoretical.FT-IR and ^1H NMR results indicated that the microstructure of the polymer was mainly 1,4-trans-butadiene with small amount of 1,2-units,and composition in the copolymers was obtained.

STUDY ON STYRENE-BUTADIENE BLOCK COPOLYMER FOR THE MODIFICATI0N OF TIRE TREAD

This paper mainly deals with the design and synthesis of a novel styrene-butadieneblock copolymer. When this copolymer is used in the tread portion of tyres, it can improvewet skid resistance and reduce rolling resistance without sacrificing its general physical-mechanical properties. The visco-elastic curve of tire tread using the novel copolymer asits rubber portion was showed. Reactivity ratios for two monomers in the polymerizingsystem were calculated. The diagrams of differelitial, integral and finite difference calculithroughout the whole molecular chain were presented. The influence of the micro- andmacro-structure of the copolymer chain on wet skid resistance and rolling resistance wasdiscussed

Thermal Stability Improvement and Structural Change of Oil Gels Formed by Styrene-Butadiene-Styrene Triblock Copolymer Induced by Adding Poly(phenylene ether)

The thermal stability of oil gels formed by styrene-butadiene-styrene triblock copolymer (SBS) was improved by adding a small amount of poly(phenylene ether) (PPE), which has a higher glass transition temperature (Tg). In naphthenic oil which is a good solvent for the butadiene blocks, but a non-solvent for the styrene blocks and PPE, PPE was selectively included into styrene blocks in SBS, and induced the increase of the Tg of these blocks. The melting temperature determined by viscoelastic measurements and softening temperature of the gels were elevated by adding PPE, while no significant change was detected by adding polystyrene. The gel became opaque by adding PPE, and partially separated phases were observed by field emission scanning electron microscopy (FE-SEM). The dependence of the viscoelastic behavior on the PPE concentration can be explained by the structural change observed by FE-SEM.

Synthesis and characterization of miktoarm star copolymer of styrene and butadiene using multifunctional macromolecular initiator

A new kind of multifunctional macromolecular initiator with Sn-C bonds and polydiene arms was synthesized by living anionic polymerization. At first, polydiene-stannum chloride （PD-SnCl3） was prepared by the reaction of n-butyl-Li （n-BuLi）, stannic chloride （SnCl4） and diene. Then PD-SnCl3 was used to react with the dilithium initiator to prepare the multifunctional organic macromolecular initiators. The result suggested that the initiators had a remarkable yield by GPC, nearly 90%. By using these multifunctional macromolecular initiators, styrene and butadiene were effectively polymefized via anionic polymerization, which gave birth to novel miktoarm star copolymers. The relative molecular weight and polydispersity index, microstructure contents, copolymerization components, glass transition temperature （Tg） and morphology of the miktoarm star copolymers were investigated by GPC-UV, ~H NMR, DSC and TEM, respectively. 2009 Xing Ying Zhang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

Synthesis and performance of miktoarm star copolymers of styrene and butadiene

A novel multifunctional macromolecular organolithium initiator （PD-Sn-（RLi）3） was prepared via living anionic polymerization and used for the synthesis of miktoarm star copolymers in cyclohexane. The average molecular weight, polydispersity index, microstructure and unit composition of the miktoarm star copolymers were characterized with GPC and 1H-NMR. Performances of the miktoarm star styrene-butadiene rubbers were investigated in comparison with those of the blend rubbers such as the tin-coupled star-shaped random copolymers of styrene-butadiene rubber（S-SBR）/natural rubber （NR） blend rubber and S-SBR/Cis-1, 4-polybutadiene rubber （Cis-BR） blend rubber.

Epoxidation of Styrene-Isoprene-Styrene Block Copolymer and Research on Its Reaction Mechanism

Styrene-isoprene-styrene（SIS） block copolymer was modified into epoxidized styrene-isoprene-styrene（ESIS） block copolymer with performic acid generated in situ from hydrogen peroxide and formic acid.The structure and property of ESIS were characterized by Fourier transform infrared（FT-IR） spectroscopy,gel permeation chromatography（GPC）,thermogravimetric/differential thermogravimetric（TG/DTG）,melt flow rate（MFR） and dynamic mechanical analysis（DMA）,and the reaction mechanism in the process of epoxidation was analyzed.The results showed that C=C double bonds of 1,4-structure were more active than that of 3,4-structure in polyisoprene chains.With epoxidation reaction proceeding,the whole tendency of molecular weight increased and molecular weight distribution widened,and MFR firstly increased and latterly decreased.The heat resistance of ESIS was superior to that of SIS.When SIS was changed into ESIS with 15.3% of mass fraction of epoxide groups,Tg of polyisoprene chains increased from-45.3 ℃ to 10.9 ℃.In the earlier period of epoxidation,some molecular chains ruptured and new substances with low molecular weight formed.However,in the latter period,crosslinking reaction between molecular chains which was initiated by epoxide groups or C=C double bonds occurred and crosslinked insoluble substances came into being.

DETERMINATION OFTHE CRYSTALLINITY IN DIFFERENT TYPE POLY (OXYETHYLENE-STYRENE)BLOCK COPOLYMERS BY X-RAY DIFFRACTION METHOD

By means of the intensity theory of X-ray scattering and the two-phase concept of high polymer, the basic formula of the crystaUinity in block copolymers has been proposed after the corrections of atomic, temperature, absorption, Lorentz and polarization factor. Application of this method to different type poly (oxyethylene-styrene)block copolymers and the same type block copolymers with different EO contents indicates that the crystallinity in poly (oxyethylene-styrene ) block copolymers increases with the increase of the EO content and decreases in the order: PEO-PS-PEO>PEO-PS>PS-PEO-PS.

Volatile Substances in Polymer Toys Made from Butadiene and Styrene

The residual levels and migration behavior of volatile substances were detected using HS-GC/MS for acrylonitrile-butadiene-styrene copolymer (ABS) toys, thermoplastic elastomer toys, and rubber toys made from 1,3-butadiene and styrene found on the Japanese market. The maximum residual level of these volatile substances was 2600 μg/g of styrene in ABS toys. In particular, the levels of known carcinogens 1,3-butadiene, benzene, and acrylonitrile are 5.3, 2.5 and 55 μg/g, which are much lower than the EU limit of 0.1%. Furthermore, some volatile substances migrated from ABS toys into water in amounts of 3 -40 ng/mL. Thermoplastic elastomer toys and rubber toys contained these volatile substances at significantly lower levels than ABS toys.

Detection of free surface composition and molecular-level structural development of styrene(S)/butadiene(B) block copolymer films during a solution-to-film process

The surface chemical structure development in solution-cast styrene(S)/butadiene(B) block copolymer films as a function of solvent evaporation time was investigated using sum frequency generation vibrational spectroscopy(SFG).The surface structure formation of the styrene(S)/butadien(B) block copolymer(30 wt% PS) films during the solution-to-film process was found to be controlled mainly by dynamic factors,such as the mobility of the PB block in solution.For SB diblock copolymers,a pure PB surface layer was formed only when the film was cast by dilute toluene solution.With increasing concentration of casting solution,PB and PS components were found to coexist on the film surface,and the morphology of the PB component on the film surface changed from cylindrical rods to spheres.For SBS triblock copolymers,a small amount of PS component existed on the surface even if the film was cast by 1.0 wt% toluene solution.In addition,PS components at the outermost layer of the film increased and the length of PB cylindrical rods on the surface decreased with increasing concentration of casting solution.

Studies on Rheological, Thermal, and Mechanical Properties of Polylactide/Methyl Methacrylate-Butadiene-Styrene Copolymer/Poly(propylene carbonate) Polyurethane Ternary Blends

Polylactide(PLA),methyl methacrylate-butadiene-styrene copolymer(MBS),and poly(propylene carbonate)polyurethane(PPCU)were blended and subjected to blown film process.The rheological,mechanical,morphological,thermal,and crystalline properties of the PLA/MBS/PPCU ternary blends and the mechanical properties of the resulting films were studied.Results of mechanical test showed that PPCU and MBS could synergistically toughen PLA.The impact strength of 50/10/40 PLA/MBS/PPCU blend(74.7 k J/m^2)was about 7.5 times higher than that of the neat PLA(10.8 k J/m^2),and the elongation at break of 50/10/40 PLA/MBS/PPCU blend(276.5%)was higher by about 45 times that of PLA(6.2%).The tear strength of PLA/MBS/PPCU films was 20 k N/m higher than that of PLA,and the elongation at break(MD/TD)of 50/10/40 PLA/MBS/PPCU films was 271.1%/222.3%,whereas that of PLA was only 2.7%/3.0%.POM observations displayed that the density of spherulite nucleation increased and the size of crystalline particles decreased with the addition of MBS.With increasing PPCU content from 5%to 20%,the density of spherulite nucleation increased and the size of crystalline particles decreased continuously,but the nucleation density of spherulites was slightly lowered with increasing PPCU content from 30%to 40%.The PLA/MBS/PPCU films exhibited excellent mechanical properties,which expanded the application range of these biodegradable films.

CHARACTERIZATION OF IRON COMPLEXES SUPPORTED ON POLYMER AND THEIR CATALYTIC ACTIVITY IN BUTADIENE POLYMERIZATION

Styrene-acrylic acid copolymer (SAAC)-supported iron complex (SAAC·Fe)was characterized and the effect of the characteristic parameters on the catalytic activity of the complex was investigated. IR spectrum suggested that the complex SAAC·Fe possesses a structure of(C)and the Fe-O bond is higher in covalency.The complex SAAC·Fe with the structure of(C)shoved a higher catalytic activity in butadiene polymerization. When Fe/-COOH molar ratio in SAAC·Fe was about 0.2 the complex gave optimum catalytic activity. The catalytic activity of SAAC·Fe with the higher content of long sequence of acrylic acid units was low. When the content of the short sequence of acrylic acid units was predominant and at the same time the content of the short sequence was approximately equal to that of the long sequence for stryrene, the activity of the complex was high.

“Living”/controlled radical copolymerization of N-phenylmaleimide and styrene using Fréchet-type dendritic initiators

Polyarylether dendrons as macroinitiators for the “living”/controlled free radical copolymerization of N-phenylmaleimide (PhMI) and styrene (St) have been demonstrated. The copolymerization was carried out in bulk or anisole with CuBr/bipy catalyst at 100–130°C. It is found that the resulting copolymers possess predetermined molecular weights and narrower polydispersities (1.18 M w/M n 1.32). The effects of reaction temperature and monomer feed on the copolymerization kinetics were investigated in detail. By using the Fineman-Ross method, the apparent monomer reactivity ratios for the atom transfer radical copolymerization of PhMI and St were determined to be r PhMI = 0.0207, and r St = 0.0484, respectively.

POLYMER-SUPPORTED LANTHANIDE COMPLEXES FOR THE POLYMERIZATION OF BUTADIENE

The characteristics of styrene-acrylic acid copolymer supported lanthanide complexes (SAAC Ln) (Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tin, Yb, and Lu) were described. A comparison of the activities of SAAC·Ln was made. It was found that in the polymerization of butadiene, a peak in activity appeared at Nd and Pr, Sin, Eu and the heavy lanthanides exhibited low or no activities. The effects of some factors on the activities were discussed. The microstructure of the polymers obtained with all the lanthanides in the series were the same and the content of cis-1, 4 polybutadiene attained was more than 98%.

Comparison of Two Methods in Determining the Composition Distribution of SBS Copolymers

The comparison of the determination of chemical composition distributions of butadiene-styrene copolymers, obtained by the formula method and experimental method of GPC, is given in this paper. The relative error of average composition was shown to be less than 5%. The formula method was found to be a more convenient and time-saving approach in the characterization of the copolymer composition distribution.

我国SBS的供需现状及发展前景分析

随着多套新建或者扩建装置的建成投产,我国苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)的生产能力稳步增长。2023年,我国SBS的生产能力达到161.5万t,表观消费量为91.5万t,预计2028年生产能力和消费量将分别达到200万和100万t。我国SBS产能过剩,市场竞争将更加激烈。今后应该慎重新建或者扩建产能,而是着力于完善现有生产技术,加快新产品和新技术的研究,不断提高产品质量,降低生产成本,在满足国内需求的同时积极开拓国外市场。

Temperature-induced Molecular Chain Motions of Styrenic Triblock Copolymers Studied by Intrinsic Fluorescence Spectra

The temperature-induced molecular chain motions of styrenic triblock copolymers （SBC）, i.e. polysty- rene-block-polybutadiene-block-polystyrene （SBS） and polystyrene-block-poly（ethylene-co-l-butene）-block-poly- styrene （SEBS）, were studied by intrinsic fluorescence method. For SBS, the glass transition temperatures （Tgs） of B block and S block obtained by intrinsic fluorescence method were in good agreement with differential scanning calorimetry measurements （DSC）. In the case of SEBS, an isoemission point was observed at about 310 nm at ele- vated temperatures, suggesting the slight conversion between the monomer and excimer emission. On this basis, the molecular chain motion of SEBS was monitored by both fluorescence intensity and excimer/monomer fluorescence ratio. Besides the Tgs of S block and EB blocks, a melting point （Tin） of weak crystalline in EB block was unambiguously determined by intrinsic fluorescence. Furthermore, it was found that the melting process directly led to the slight loosening of PS segments in interface and consequently the reduction of the amount of excimer. A reasonable mechanism was proposed to describe the molecular chain movements and phase transitions of SEBS upon heating. Moreover, the influence of temperature on the apparent activation energy of non-radiative process （ E^T ） around Tg of S block was much stronger than that around Tg of B or EB blocks.

星形多臂丁苯共聚物的分子结构设计与合成

以正丁基锂为引发剂、苯乙烯与丁二烯为单体、双四氢糠丙烷为极性结构调节剂、六氯乙硅烷为偶联剂,采用活性负离子聚合技术设计并合成了一系列具有星形结构的多臂丁苯共聚物(S-g-SSB-6)。使用凝胶渗透色谱分析了S-g-SSB-6的分子量及其分布、偶联臂数和偶联效率,使用旋转流变仪测试了S-g-SSB-6、以SiCl_(4)为偶联剂的星形多臂丁苯共聚物及线型结构丁苯共聚物(L-SSB)的流变性能,并考察了支链长度和支链柔顺性对S-g-SSB-6流变性能的影响。结果表明,S-g-SSB-6的偶联臂数达到4.1、偶联效率均大于80%;相同重均分子量下S-g-SSB-6的熔体黏度较L-SSB更低、流体流动性更好;当支化度相同时,S-g-SSB-6的熔体黏度随着单臂分子量和分子链刚性的增加而增大。

FDM用ABS复合材料的改性及其应用研究进展

丙烯腈-丁二烯-苯乙烯共聚物(ABS)具有良好的力学性能和可加工性。近年来,随着熔融沉积成型(FDM)三维(3D)打印技术的不断成熟和发展,ABS及其各类改性复合材料也相应被广泛应用于FDM。本文重点基于FDM技术,首先系统整理了金属类填料、无机非金属类填料、有机高分子类填料、回收废旧聚合物类填料等改性ABS基复合材料的现状,并对其相关性能进行了归纳。同时,对相应的各类ABS改性复合材料的FDM打印制品在医学、民用工业、军用电磁与吸波等领域的前沿应用进行了综述。最后,结合FDM打印技术和ABS改性现状,对未来FDM打印方法以及ABS改性技术提出了几点思考。

SEBS/sCFO复合涂层的制备及防污性能

目的合成可抑制海洋生物吸附的磁性纳米微球,制备具有微纳结构的新型防污复合材料。方法首先采用溶剂热法和一步吸附法制备铁酸钴/苯并三唑(CFO/BTA,sCFO)磁性纳米球,将sCFO与嵌段共聚物聚(苯乙烯-乙烯-丁烯-苯乙烯)(SEBS)复合,通过喷涂法制备SEBS/sCFO复合涂层。使用透射电子显微镜、X射线衍射仪、傅里叶变换红外光谱仪、热重分析仪等分析sCFO的微观形貌、晶体结构和化学组成等,通过扫描电子显微镜、接触角测试、蛋白吸附实验、硅藻吸附实验等分析sCFO添加量对SEBS/sCFO复合涂层的表面形貌和防污性能的影响。结果所制备的sCFO为球形结构,尺寸为60~70 nm,饱和磁化强度为44.7 emu/g,其中苯并三唑含量约为32.3%。SEBS涂层的表面因为相分离而呈现褶皱状形貌,SEBS/sCFO复合涂层的表面形貌也因磁性纳米粒子的诱导作用而发生取向,随着sCFO添加量的增加,SEBS/sCFO复合涂层的相分离结构发生变化,提高了SEBS/sCFO复合涂层的抗蛋白吸附性能和抗硅藻吸附性能。结论sCFO纳米球的添加提高了复合涂层的抗蛋白吸附性能、抗硅藻吸附性能,通过sCFO纳米球对SEBS热塑性弹性体表面结构的诱导作用,为研制具有不同微纳表面的新型防污涂层提供了新方法,在海洋防污领域具有潜在的应用前景。