Synthesis of platinum acetylide complexes and their application in curing silicone rubber by hydrosilylation

Eight platinum acetylide complexes have been synthesized and characterized. The catalytic properties of these complexes in curing silicone rubber by hydrosilylation have been tested. Among the complexes tested, trans‐Pt(PPh₃)₂[―C≡CC(CH₃)₂OSi(CH₃)₃] ₂ (2), trans‐Pt(PPh₃)₂[―C≡CC(CH₃)₂OSi(CH₂CH₃)₃]₂ (3), trans‐Pt(PPh₃)₂[―C≡CC(CH₃)₂OSiPh(CH₃)₂]₂ (4), trans‐Pt(PPh₃)₂[―C≡C(C₆H₁₀)OSi(CH₃)₃]₂ (6), trans‐Pt(PPh₃)₂[―C≡C(C₆H₁₀)OSi(CH₂CH₃)₃]₂ (7), and trans‐Pt(PPh₃)₂[―C≡C(C₆H₁₀)OSiPh(CH₃)₂]₂ (8) exhibited sufficiently long pot‐lives (15 days) at room temperature and short silicone rubber curing times of 10–35 min at 100°C or 1–5 min at 120°C. Copyright © 2012 John Wiley & Sons, Ltd.     

烯烃可控/活性正离子聚合新方法与新工艺及其应用

<正>离子聚合是高分子科学中重要的聚合方法之一,也是制备聚异丁烯或丁基橡胶等关键材料不可或缺的聚合方法.本文总结了异丁烯、苯乙烯及其衍生物等单体可控/活性正离子聚合的新引发体系、聚合反应特征的调节与转化、水相介质中正离子聚合新方法与新工艺、微观分子混合与正离子聚合新工艺及其用于设计合成异丁烯基聚合物.这些方法与技术是发展高效节能与绿色减排先进聚合物生产技术的重要途径,部分研究成果已在产业化中得到应用与验证.发展可控/活性正离子聚合新体系、新方法与新工艺,为实现绿色低碳高分子化工过程及相关产品工程(新结构、新功能、高性能与高品质)提供了新思路与新技术.     

Effects of rubber type on the curing and physical properties of silica filled rubber compounds

As environmental regulations are getting stricter, tire industries for automobiles have shown much interest in substituting silica for conventional carbon black partially or entirely. To take full advantage of silica as fillers for rubbers, it is essential to find a reasonable rubber system that shows an excellent performance with silica reinforcement. Therefore, in this study, several different rubber compounds comprising the same amount of silica were prepared with several different rubber systems, respectively. The processability, curing characteristics, and mechanical and viscoelastic properties of the rubber compounds were investigated to analyze the performance of the rubber compounds as tire tread materials. Among the rubber compounds studied, SBR1721 compound comprising natural rubber (NR) and styrene butadiene rubber (SBR) with high styrene content was considered the most appropriate for application to tire tread materials. Copyright © 2008 John Wiley & Sons, Ltd.     

Grafting of hyperbranched poly(amidoamine) onto waste tire rubber powder and its potential application as the curing agent for epoxy resin

To realize the high‐valued application of waste tire rubber (WTR), hyperbranched poly(amidoamine) (PAMAM) were synthesized from the surface of WTR powders to endow its chemical reactivity. The hyperbranched PAMAM‐grafted WTR powders containing a large amount of amine groups on their surface were obtained through “divergent procedure.” First, methyl methacrylate‐grafted WTR powders (MMA‐g‐WTR) were prepared by ozone‐induced grafting polymerization. Afterwards, Michael reaction and subsequent amidation reactions were carried out repetitively to obtain hyperbranched PAMAM chains grafted from the surface of the MMA‐g‐WTR powders. The resulting hyperbranched PAMAM‐grafted WTR powders exhibit good dispersibility in water. Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, and thermogravimetric analysis demonstrate the successful grafting of hyperbranched PAMAM on WTR surface. The hyperbranched PAMAM‐grafted WTR powder could be utilize as curing agent and potential toughener for epoxy resin due to abundant amine groups and elastomeric feature of WTR. Differential scanning calorimetry shows that the hyperbranched PAMAM‐grafted WTR powders can be used as effective curing agent for epoxy resin. Copyright © 2011 John Wiley & Sons, Ltd.     

环氧化丁基橡胶的合成与表征

以正己烷为溶剂、间氯过氧苯甲酸(mCPBA)为环氧化试剂对丁基橡胶(IIR)进行环氧化改性研究,考察了原料配比、反应温度、胶液浓度等反应条件对环氧化反应的影响,并对反应过程中发生的副反应进行了探究.采用核磁共振氢谱(1H-NMR)对合成的环氧化丁基橡胶(EIIR)的结构进行了表征,并对环氧化度进行了定量计算.确定了最优...     

Photocrosslinking of acrylated natural rubber

Photocrosslinkable elastomers with pendent acrylate groups have been synthesized by ringopening reaction of epoxidized natural rubber with acrylic acid. The kinetics of the acrylation reaction has been studied by infrared spectroscopy and shown to obey a simple first-order law. The acrylated natural rubber undergoes a fast crosslinking-polymerization when it is exposed to UV radiation in the presence of an aryl ketone photoinitiator, with formation of a tridimensional polymer network within a few seconds. The cure kinetics has been studied in real time by monitoring the disappearance of the IR absorption of the grafted acrylate double bond. The rate of polymerization was found to increase linearly with the degree of acrylation of the rubber, reaching values up to 3 mol kg^?1 s^?1. The isoprene double bond, which is inactive in virgin natural rubber, also undergoes polymerization upon UV exposure when epoxy or acrylate groups are present. The UV-cured polymer becomes totally insoluble in the organic solvents and exhibits remarkable mechanical properties, such as hardness, flexibility, and impact resistance. The gel fraction and the hardness were both shown to increase with the degree of acrylation and with the cure extent. © 1993 John Wiley & Sons, Inc.     

Synthesis and properties of UV curable polyvinylsilazane as a precursor for micro‐structuring

Photosensitive acrylated polyvinylsilazanes were prepared by reacting a diacrylate containing compound, 1,1‐bis (acryloyloxyethyl) ethyl isocyanate (BAEI), with polyvinylsilazane (PVSZ) and utilized as an inorganic photoresist for generating SiCN‐based ceramic microstructures. The acrylate‐modified polymers (m‐PVSZ) were characterized by ¹H‐NMR, ¹³C‐NMR and FT‐IR methods to determine the chemical reaction mechanism. Differential photo‐calorimeter and FT‐IR analysis were employed to examine its photosensitive properties. Line patterns were fabricated by a UV nano‐imprinting method; multi‐layered octagon structures were fabricated by a two‐photon absorption stereolithography process. The results indicate that m‐PVSZ is quite a novel inorganic photoresist for the fabrication of micro ceramic structures. Copyright © 2015 John Wiley & Sons, Ltd.     

木质素基环氧丙烯酸酯的合成及紫外光固化

正木质素是地球上一种储量十分丰富的可再生资源,可生物降解[1,2].木质素结构中含有大量羟基,主要以酚羟基和醇羟基形式存在,可与许多化合物发生化学反应制得木质素基环保材料,是最有前途的生物质资源之一[3].但工业木质素纯度较低,对其利用多为直接混合,如水泥减水剂等低端领域.环氧丙烯酸酯(EA)作为紫外光固化的预聚体,在紫外光照射下可快速固化,其黏接性高,耐化学药品性能优异,应用广泛[4,5].因此降低EA的成本,对其进行改性是近年来该领域的研究热点[6].本文以工     

Synthesis of UV-curable liquid crystalline diacrylates for the application of polarized electroluminescence

Two series of UV-curable rod-like diacrylates containing bis-tolane (M1-M5) and bis-stilbene (M6-M10) mesogens were synthesized. All of the diacrylates were prepared through convergent syntheses involving palladium-catalysed coupling reactions. The thermal transitions and mesomorphic properties of the diacrylates were characterized by differential scanning calorimetry and optical microscopy. All the bis-tolane-based monomers reveal nematic phases, except M5 which shows no mesomorphic behaviour. For the bis-stilbene based monomers, most show no mesomorphic behavior and only M7 and M9 exhibit a SmA phase.     

Cross‐linking and properties of rubber magnetic composites cured with different curing systems

Rubber magnetic composites were prepared by incorporation of strontium ferrite into rubber compounds based on acrylonitrile butadiene rubber and ethylene propylene diene monomer rubber. The sulfur, peroxide, and mixed sulfur/peroxide curing systems were introduced as cross‐linking agents for rubber matrices. The aim was to investigate the influence of curing system composition on curing process and cross‐link density of composite materials. Then, static and dynamic mechanical properties and thermal and magnetic characteristics were investigated in relation to the cross‐link density of rubber magnetic composites and structure of the formed cross‐links. The changes of dynamical and physicomechanical properties were in close correlation with the change of cross‐link density, whereas the tensile strength of magnetic composites showed increasing trend with increasing amount of peroxide in mixed curing systems. On the other hand, thermal conductivity and magnetic characteristics were found not to be dependent on the curing system composition.     

可紫外光固化的聚乙烯基硅氮烷合成与表征

采用带丙烯酸酯基团的烯丙基溴化合物(4-溴丁烯酸乙酯)和聚乙烯基硅氮烷发生取代反应,实现了丙烯酸酯基团在聚乙烯基硅氮烷主链上的链接.采用质子核磁共振谱(1H-NMR)和二维质子核磁共振谱(2D-1H-1H-NMR)对分子结构进行了表征,采用光学差热分析仪(Photo-DSC)和傅立叶转换红外光谱仪(FT-IR)测试了改性高分子的光敏性能,用热重分析仪(TGA)分析了产物在高纯氮气氛围下的陶瓷收率.结果表明,通过分子改性,交联固化时间从改性前的20min减少到1min之内,功能化的聚乙烯基硅氮烷可以在光刻蚀工艺中作为负性光刻胶使用.     

Synthesis and properties of oxetane‐based polysiloxanes used for cationic UV curing coatings

The polysiloxanes end‐capped with oxetane group (PSiO‐H and PSiO‐L) were synthesized via hydrosilylation reaction based on α,ω‐dihydrogen‐terminated polydimethylsiloxanes with a higher (0.23%, PDSi‐H) and lower (0.12%, PDSi‐L) hydrogen amount. The molecular structures were characterized by FT‐IR and ¹H NMR spectroscopy. The polysiloxanes were added into a commercial oxetane‐based resin, 3,3′‐(oxydi(methylene)) bis(3‐ethyloxetane) (DOX), as an additive to prepare a series of cationic UV curable formulations. The photo‐DSC results showed that the maximum photopolymerization rate decreased while the oxetane conversion increased with the polysiloxane content increasing. The surface hydrophobic property of cured films was improved having the water contact angles of 97° and 99° compared with 82° of the cured DOX film with only 1 wt% PSiOs, respectively. The dynamic mechanical thermal analysis results showed that both the storage modulus on the rubbery plateau region and the glass transition temperature decreased with increasing PSiO‐H loading. Moreover, the decrease became more obvious as PSiO‐L was added instead of PSiO‐H due to its lower concentration of oxetane group. The thermal stability of cured films was enhanced by the addition of PSiOs from the thermogravimetric analysis. And the DOX/PSiO‐H film possessed higher thermal degradation temperatures than DOX/PSiO‐L film. Copyright © 2011 John Wiley & Sons, Ltd.     

Synthesis of graft copolymer derivatives of brominated poly(isobutylene-co-isoprene)

Strategies for preparing graft copolymers from brominated poly(isobutylene-co-isoprene) (BIIR) are demonstrated. Selective dehydrohalogenation of the allylic bromide functionality within BIIR to give an exo-conjugated diene is described, along with subsequent cycloadditions of maleic anhydride (MAn) and its mono-ester and di-ester derivatives. Alcoholysis of the bicyclic anhydride product of BIIR dehydrobromination/MAn cycloaddition is used to produce an IIR-g-PE copolymer in low yield. An alternate approach involving bromide displacement from BIIR by the salts of maleate half-esters is shown to be an efficient means of generating isobutylene-rich copolymers containing polyethylene, polyethylene oxide and polycaprolactone grafts.     

Synthesis of peroxide‐curable butyl rubber via suzuki–miyaura coupling of halogenated butyl rubber with 4‐vinylphenylboronic acid

The Suzuki–Miyaura coupling reaction of brominated butyl rubber (BIIR) and/or chlorinated butyl rubber with a mixture of 4‐vinylphenylboronic acid and phenylboronic acid was carried out in THF under various conditions using a di‐μ‐chlorobis [5‐hydroxy‐2‐[1‐(hydroxyimino‐κN)ethyl]phenylκC] palladium(II) dimer, which is a type of cyclopalladated complex, as a catalyst. When BIIR and a small amount (Pd/Br ≈ 1/1000) of complex were used as the substrate and catalyst, respectively, a 4‐vinylphenyl and phenyl group could be introduced to butyl rubber in a high yield. Isomerization of the exo carbon–carbon double bond in BIIR was observed during the coupling reaction to give a cis and trans endo structure. The peroxide curing behavior of the resulting polymer at 170 °C indicated that the polymer could be cured by dicumyl peroxide, and the maximum torque of the resulting material, which reflects the crosslink density, was controllable by the composition of the boronic acids used. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

一种含螺吡喃和肉桂酸酯双光功能基团的光致变色染料的合成与性能

合成了一种含有光致聚合肉桂酸酯基团的新型光致变色螺吡喃染料,研究其与普通螺吡喃染料在不同高分子材料中的光致变色和热退色过程(PMMA和PVCi).通过UV-Vis光谱、NMR谱和IR光谱研究了新型染料中的肉桂酸酯基团的光致聚合过程,考察了其对螺吡喃结构的光致变色显色体热稳定性的影响.     

Thermo-optical study of UV cured polyether urethane diacrylate films with dispersed octadecanol

Thermally reversible light scattering (TRLS) films are prepared from ultraviolet (UV) curing of polyether urethane diacrylate (PEUDA) with dispersed low molecular weight 1-octadecanol (OD). Depending on the temperature, the OD domains are crystalline or amorphous and this produce opaque or transparent films in a reversible way. Stable optically transparent and light scattering states are obtained after 100 successive heating–cooling cycles. Moreover, morphologies of the OD domains could be varied significantly with the cure temperature and this led to notable discrepancy in optical properties. By using an UV-mask and curing in two steps at different temperatures, complex patterns could be recorded in the film that were encoded at high temperatures (60 °C) and revealed at low temperatures (i.e., at room temperature), which makes the film a candidate for thermo-optical recording medium.     

Synthesis of urethane acrylates modified by linseed oil and study on EBC coatings

In this paper, five different structural urethane acrylates modified by linseed oil were synthesized and then properties of their electron beam cured (EBC) coatings, i.e., adhesion, gloss, flexibility, impact resistance, hardness, tensile strength and elongation were studied. It was shown that these synthesizing conditions of urethane acrylates modified by linseed oil were temperate. Effect of structure of urethane acrylates modified by linseed oil on these properties of their EBC coatings was obvious, except gloss. According to synthetical properties of EBC coatings, the optimum oligomer among these was No. A, whose main chains were formed by hexane diacid, average functionality was 2, and oil content was 25.5%. With increasing of absorbed doses, these properties of EBC coatings, except gloss, changed correspondingly. It was advisable that absorbed dose wasn’t greater than 180 kGy. At higher absorbed doses, cobaltous naphthenate had obvious effect on these properties of EBC coatings, whose oil content of linseed oil was rather high.     

Field‐induced bending deformation of various rubber films

The field‐induced bending deformation of various rubber films was measured. The deformation tended to increase with the increase in the conductivity of the films. In addition, the effect of doping with tetracyanoethylene (TCNE) was also studied. This doping significantly enhanced the bending deformation and conductivity when the film was made of acrylonitrile‐butadiene rubber. The tip of the film (5 × 30 mm², 0.28 mm thick) moved by 3 mm due to the bending deformation induced by the applied voltage (140 V). Such a rubber film may find applications as a polymer actuator. Copyright © 2007 John Wiley & Sons, Ltd.     

Synthesis and characterization of poly(ethylene oxide‐co‐ethylene carbonate) macromonomers and their use in the preparation of crosslinked polymer electrolytes

Methacrylate‐functionalized poly(ethylene oxide‐co‐ethylene carbonate) macromonomers were prepared in two steps by the anionic ring‐opening polymerization of ethylene carbonate at 180 °C, with potassium methoxide as the initiator, followed by the reaction of the terminal hydroxyl groups of the polymers with methacryloyl chloride. The molecular weight of the polymer went through a maximum after approximately 45 min of polymerization, and the content of ethylene carbonate units in the polymer decreased with the reaction time. A polymer having a number‐average molecular weight of 2650 g mol^?1 and an ethylene carbonate content of 28 mol % was selected and used to prepare a macromonomer, which was subsequently polymerized by UV irradiation in the presence of different concentrations of lithium bis(trifluoromethanesulfonyl)imide salt. The resulting self‐supportive crosslinked polymer electrolyte membranes reached ionic conductivities of 6.3 × 10^?6 S cm^?1 at 20 °C. The coordination of the lithium ions by both the ether and carbonate oxygens in the polymer structure was indicated by Fourier transform infrared spectroscopy. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2195–2205, 2006     

大分子阳离子光引发剂聚苯乙烯-碘(鎓)六氟锑酸盐的合成及其感光性能的研究

本文用羟基对甲苯磺酰氧基碘苯与聚苯乙烯进行亲电取代反应,得到大分子阳离子碘鎓盐光引发剂聚苯乙烯碘鎓-六氟锑酸盐(PS-I·SbF₆).用核磁共振仪、傅立叶红外光谱仪、凝胶渗透色谱仪、差示扫描量热仪、紫外分光光度仪对其进行了表征.与小分子碘鎓盐系光引发剂相比,PS-I·SbF₆的紫外最大吸收波长λ_max红移,在240-270 nm范围内有较强的吸收;固化成膜后其相对迁移率较小分子光引发剂有显著下降.初步研究了PS-I·SbF₆在环氧体系中的光固化性能,结果表明该体系有较好的光固化和后固化特性.