多官能团单体对甲基乙烯基硅橡胶的辐射交联敏化效应

研究了在γ射线的作用下多官能团单体对甲基乙烯基硅橡胶(MVQ)的辐射交联敏化效应.结果表明,加入多官能团单体的MVQ经过辐射发生交联反应;四甘醇二甲基丙烯酸酯、三烯丙基异氰尿酸酯、三羟甲基丙烷三甲基丙烯酸酯(TMPTMA)3种多官能团单体对MVQ的辐射交联具有明显的敏化作用,其中TMPTMA的敏化效果最好,其最佳用量为2份;加入TMPTMA或者加大辐射剂量,MVQ的损耗因子提高,玻璃化转变温度升高;当辐射剂量为40 kGy时,添加2份TMPTMA的MVQ的物理机械性能达到最佳.     

多官能团不饱和单体对CR辐射硫化的敏化效应

用密炼机将９种多官能团不饱和单体（ＰＦＭ）分别与ＣＲ在８０℃混炼８ｍｉｎ后，于１３０℃，１５ＭＰａ条件下在平板硫化机上压制成０．５ｍｍ厚的试样。该试样用电子加速器产生的１．００ＭｅＶ电子束辐照引发硫化反应。结果表明，硫化胶的交联密度（Ｍｃ－１）线性正比于辐射吸收剂量（Ｄ）和单体加入量（Ｃ０），即Ｍｃ－１＝（Ａ＋ＫＣ０）Ｄ，且Ｋ随ＰＦＭ的比不饱和度增大而提高。     

溴化1-十六烷基-3-乙烯基咪唑型离子液体的制备及聚合性研究

以N-乙烯基咪唑、溴代十六烷为原料,经亲核取代反应合成溴化1-十六烷基-3-乙烯基咪唑([HDVIM]Br)离子液体。并以该离子液体为单体,偶氮二异丁腈(AIBN)为引发剂,制备聚离子液体p[HDVIM]Br。采用红外光谱(FTIR)、核磁共振仪(~1H NMR)和元素分析、凝胶色谱仪(GPC)、热重分析仪(TGA)、X-射线衍射仪(XRD)及电导率对其进行结构与性能测试与分析。结果表明,[HDVIM]Br具有可聚性,且为无定形非晶结构。[HDVIM]Br的电导率随温度升高逐渐增大,随着浓度增加而增加;溴化1-十六烷基-3-乙烯基咪唑离子液体聚合物p([HDVIM]Br)的数均分子量为3.68×10~4 g/mol。     

溴化1-十六烷基-3-乙烯基咪唑型离子液体的制备及聚合性研究

以N-乙烯基咪唑、溴代十六烷为原料,经亲核取代反应合成溴化1-十六烷基-3-乙烯基咪唑([HDVIM]Br)离子液体。并以该离子液体为单体,偶氮二异丁腈(AIBN)为引发剂,制备聚离子液体p[HDVIM]Br。采用红外光谱(FTIR)、核磁共振仪(¹H NMR)和元素分析、凝胶色谱仪(GPC)、热重分析仪(TGA)、X-射线衍射仪(XRD)及电导率对其进行结构与性能测试与分析。结果表明,[HDVIM]Br具有可聚性,且为无定形非晶结构。[HDVIM]Br的电导率随温度升高逐渐增大,随着浓度增加而增加;溴化1-十六烷基-3-乙烯基咪唑离子液体聚合物p([HDVIM]Br)的数均分子量为3.68×101H NMR)和元素分析、凝胶色谱仪(GPC)、热重分析仪(TGA)、X-射线衍射仪(XRD)及电导率对其进行结构与性能测试与分析。结果表明,[HDVIM]Br具有可聚性,且为无定形非晶结构。[HDVIM]Br的电导率随温度升高逐渐增大,随着浓度增加而增加;溴化1-十六烷基-3-乙烯基咪唑离子液体聚合物p([HDVIM]Br)的数均分子量为3.68×10⁴ g/mol。     

聚(N-乙烯基异丁酰胺)接枝聚苯乙烯微球的合成研究

合成了数均相对分子质量为 35 0 0和 6 30 0的两种聚 (N 乙烯基异丁酰胺 ) (PNVIBA)大分子单体 ,并以此大分子单体与苯乙烯 (St)在V(乙醇 )∶V(水 ) =7∶3的混合溶剂中进行自由基分散共聚 ,得到了稳定分散的PNVIBA接枝聚苯乙烯 (PSt)高分子微球。研究发现微粒的粒径随聚合体系中大分子单体相对分子质量和质量浓度的增加而减小 ,并发现当混合溶剂中水的体积分数增加到 ρ(水 ) =35 %时 ,微球的形态发生明显变化。     

溴化1-乙烯基-3-烷基咪唑离子液体的电化学性能

合成了溴化1-乙烯基-3-烷基咪唑([VAIM]Br)离子液体,采用FTIR、¹H NMR、TG及DSC进行了表征,并系统研究了[VAIM]Br的电化学性能。结果表明:在298.15～323.15 K内,[VAIM]Br的电导率(σ)与温度符合Arrhenius方程,电导活化能随[VAIM]⁺上烷基链的增长而降低。分别以水、甲醇和乙醇为溶剂的[VAIM]Br溶液的电导率均随浓度的增大而显著增大,且σ(水)>σ(甲醇)>σ(乙醇)。通过电导法确定了[VAIM]Br在水、甲醇、乙醇中的临界胶束浓度,分别约为6.8×10^-6、1.5×10^-5、2.0×10^-5 mol·L^-1,表面活性优异。[VAIM]Br的电化学窗口在1.6～2.5 V,其电化学稳定性随[VAIM]⁺上烷基链的增长而逐渐降低。     

高分子阻燃剂溴化聚苯乙烯的应用

以高分子溴化聚苯乙烯(BPS)协同三氧化二锑(Sb2O3)作为复合阻燃剂,对聚对苯二甲酸丁二醇酯(PBT)进行改性。研究了复合阻燃剂对PBT的燃烧性能,电性能及力学性能的影响。结果表明,复合阻燃剂BPS/Sb2O3对PBT具有良好的阻燃效果,对其电性能影响很小,少数力学性能有所下降。在PBT中添加BPS/SbO复合阻燃剂的质量分数为20%时,阻燃PBT的垂直燃烧达到FV-0级。     

多官能化SBS的制备及其在沥青中分散性研究

以聚苯乙烯-丁二烯-苯乙烯三嵌段共聚物(SBS)为原料,N-乙酰-L-半胱氨酸(NAC)为改性剂,偶氮二异丁腈为引发剂,二恶烷(DOA)为溶剂,通过巯基-烯加成接枝反应制备了支链多官能化SBS(SBS-g-NAC,含酰胺基、羧基),考察了不同官能度的SBS在沥青中的分散性。通过拟合反应条件与SBS-g-NAC官能度的相关实验数据,建立了官能度与反应时间、温度和改性剂用量之间的关联性方程。结果表明,该关联性方程能够很好地拟合实验数据,并可根据所需官能度来确定工艺参数;官能度13.81%的SBS-g-NAC能够明显改善其在沥青中的分散性。     

多官能化SBS的制备及其在沥青中分散性研究

以聚苯乙烯-丁二烯-苯乙烯三嵌段共聚物(SBS)为原料,N-乙酰-L-半胱氨酸(NAC)为改性剂,偶氮二异丁腈为引发剂,二恶烷(DOA)为溶剂,通过巯基-烯加成接枝反应制备了支链多官能化SBS(SBS-g-NAC,含酰胺基、羧基),考察了不同官能度的SBS在沥青中的分散性。通过拟合反应条件与SBS-g-NAC官能度的相关实验数据,建立了官能度与反应时间、温度和改性剂用量之间的关联性方程。结果表明,该关联性方程能够很好地拟合实验数据,并可根据所需官能度来确定工艺参数;官能度13.81%的SBS-g-NAC能够明显改善其在沥青中的分散性。     

Crosslinking of cis-1,4-polyisoprene rubber by electron beam irradiation

Various unsaturated polyfunctional monomers were kneaded into cis-1,4-polyisoprene containing fillers under 80°C and then irradiated using an electron beam accelerator to prepare vulcanized rubber with good quality. Results showed that 2G (diethyleneglycol dimethacrylate) is the best sensitizer. The optimal tensile strength of vulcanized IR was obtained by using 14 phr 2G and irradiated to 180 kGy. Compared with the sulfur vulcanizate, greater values of tensile strength, elongation at break, and 100% stress were found with the radiation-cured IR. Their Young's modulus and tan σ were similar. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 113–116, 1997     

Radiation crosslinking of poly(butylene succinate) in the presence of low concentrations of trimethallyl isocyanurate and its properties

Poly(butylene succinate) (PBS) with different molecular weights was irradiated using an electron beam (EB) in the presence of polyfunctional monomers at ambient temperature. Five polyfunctional monomers were used in this work. The highest amount of gel fraction was achieved when PBS was blended with trimethallyl isocyanurate (TMAIC). The amount of TMAIC introduced strongly influenced the amount of resulting gel. It was determined that the crosslinked PBS sample containing 1% TMAIC had a higher glass‐transition temperature than did the original PBS. It was also observed that the presence of crosslinking bonds in the irradiated PBS greatly improved its heat stability and diminished its ability to biodegradate. Accordingly, it can be concluded that crosslinked PBS in the presence of TMAIC significantly improved its heat resistant properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2238–2246, 2003     

Intermolecular crosslinking of poly(acrylic acid) in aqueous solution by electron beam irradiation

Poly(acrylic acid) (PAA) was dissolved in water, and the solution was irradiated with high‐energy electrons. The formation of macroscopic gel was studied as a function of the radiation dose, the pH of the aqueous solution, and the concentration of added salt. Gelation by intermolecular crosslinking was found at low pH values of 2–4, whereas at pH greater or equal to 5, no gel was formed by electron beam irradiation. Nevertheless, by adding monovalent salt the gel formation was enhanced at intermediate pH values. The intermolecular crosslinking was assumed to be inhibited by electrostatic repulsive forces when the macromolecules of PAA are negatively charged and the ionic strength of the solution is low. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

溴化丁基橡胶的热可逆共价交联

利用季铵化反应的热可逆特性,采用含有叔胺官能团的聚合物替代传统交联剂,研究了溴化丁基橡胶(BIIR)的交联反应活性及交联的热可逆性.结果表明,硫化温度和硫化时间对交联BIIR的凝胶含量有显著影响,在160 ℃×30 min的硫化条件下,交联剂呈现出较高的交联活性;不同温度下的转矩测定和190 ℃二次热压的塑性流动证实交联BIIR具备热塑加工性.     

Grafting of butyl acrylate and methyl methacrylate on butyl rubber using electron beam radiation

Being nonpolar in nature, butyl rubber (IIR) has poor compatibility toward polar polymers and fillers. It can be improved by grafting polar substrates on the butyl elastomer. Radiation‐induced polymer processing is getting increasing interest, as it leads to new and improved polymers with desirable and interesting properties. In this investigation, electron beam radiation has been used to graft methyl methacrylate (MMA) and butyl acrylate (BA) on IIR. This process has several advantages over conventional grafting processes such as cationic polymerization (which needs very low temperature and stringent reaction conditions) and solution radical polymerization (which often needs solvent removal and recycling). The grafted polymers were characterized by using ¹H NMR, IR, TGA, and SEM analysis. The degree of grafting increases with a decrease in irradiation dose as well as with an increase in monomer concentration. It was observed that there was a decrease in intrinsic viscosity in irradiated IIR samples, indicating the chain scission. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1340–1346, 2006     

Thermally stable bromobutyl rubber with a high crosslinking density based on a 4,4′‐bismaleimidodiphenylmethane curing agent

The development of thermally stable bromobutyl rubbers has been a challenge in rubber chemistry and engineering. In this circumstance, 4,4′‐bismaleimidodiphenylmethane (BMI) was newly applied as a novel crosslinking agent for thermally stable brominated isobutylene–isoprene rubber (BIIR) with a high crosslinking density. With oscillating disk rheometry and differential scanning calorimetry, the curing characteristics of BIIR were systematically investigated with respect to the content of BMI. We found that BMI alone could crosslink BIIR at higher temperature, and a corresponding possible chemical reaction mechanism was proposed. With the introduction of zinc oxide, the curing reaction of BIIR with BMI was significantly accelerated, and the resulting vulcanizate provided a higher state of curing with excellent overcure reversion stability even at a temperature of 190 °C for 2 h. The content of the dicumyl peroxide (DCP) reaction accelerator was also optimized to be BMI/DCP = 1:0.05 on the basis of considerations of the curing rate, scorch safety, maximum rheometric torque, and reversion resistance at 160 °C. Compared with the conventional sulfur‐cured BIIR, the BMI‐cured BIIR exhibited a higher crosslinking density with a superior low compression set property at elevated temperatures and an excellent thermal stability. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44092.     

Influence of electron beam irradiation on properties of fluorine‐containing poly(aryl ether ketone)s

The influence of electron beam irradiation on the properties of fluorine‐containing poly(aryl ether ketone)s (F‐PEK), derived from 2,3,4,5,6‐pentafluorobenzoic acid, was examined. Irradiation was performed with an electron beam at a dose of 3.63 × 10³ Gy s^?1 for which the corresponding doses were 29.0, 51.0, and 94.5 MGy. Tensile strength at break increased up to a dose of 29.0 MGy and then decreased very slightly with irradiation. Elongation at break was more susceptible to irradiation and decreased drastically to one tenth at a dose of 29.0 MGy. Young's modulus was enhanced by the irradiation. F‐PEKs were changed from elastic materials to strong and brittle materials by irradiation. Relaxation of the viscoelastic property shifted toward higher temperature by irradiation. These tensile and viscoelastic property changes were attributed to the formation of a bulkier and more rigid structure by crosslinking. The fluorine atoms attached to the 1,4‐phenylene moiety in F‐PEKs were surprisingly susceptible to the irradiation and were completely lost at a dose of 29.0 MGy. The π‐electron conjugated aromatic structure was concurrently developed during irradiation. Further, polar functional groups such as carboxyl group and ester group were generated by chain scission and rearrangement. The F‐PEKs retained their good transparency and the thermal stability was significantly improved after irradiation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 157–166, 2004     

Dynamic mechanical properties of electron beam modified fluorocarbon rubber

The dynamic mechanical properties of electron beam modified fluorocarbon rubbers (terpolymer: F content, 68% and H, 1.4%; copolymer: F content, 65% and H, 1.9%) were studied. With an increase in the radiation dose, the loss tangent maximum decreases and the glass transition temperature increases. The influence of the polyfunctional vinyl monomer, trimethylolpropane triacrylate (TMPTA), is to decrease the loss tangent value, especially at higher doses. At a particular level of the multifunctional monomers tripropylene glycol diacrylate (TPGDA), TMPTA, and tetramethylolmethane tetracrylate, the dynamic mechanical thermal analysis indicated the lowest degree of crosslinking for the system based on TPGDA. MgO-based systems register a decrease of the loss tangent peak height and an increase in the storage moduli compared to the control rubber. The results are explained on the basis of gel fraction, scission reactions, and structural changes as measured with the help of IR-attenuated total reflectance spectroscopy. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 2079–2087, 1998     

A crosslinking method of UHMWPE irradiated by electron beam using TMPTMA as radiosensitizer

Trimethylolpropane trimethylacrylate/Ultra high molecular weight polyethylene (TMPTMA/UHMWPE) composite and pure UHMWPE plates were made by compression molding and electron beam (EB) irradiation crosslinking methods. Fourier transform infrared spectroscopy (FTIR), Soxhlet extractor, electromechanical tester, and wear tester were used for the characterization of the structure, mechanical properties, and tribological performance of the crosslinked UHMWPE. FTIR analyses show that trans‐vinylene (965 cm^?1) absorption increases with the increasing dose and the trans‐vinylene intensity of TMPTMA/UHMWPE is higher than that of UHMWPE at the same dose, and Soxhlet experiments reveal that gel fraction increases with the increasing dose, both proving that crosslinking took place in all the irradiated samples. The results of the tensile tests indicate a significant decrease in elongation at break, but the stress of UHMWPE increases to 47 MPa at 10 kGy and then decreases with the increasing dose. The stress of TMPTMA/UHMWPE composites keeps at about 39 MPa before 50 kGy and then decreases with the increasing dose because of plasticization effect. The stress changes indicate that crosslinking and degradation occurred at the same time. Wear rate of 100 kGy 1% TMPTMA/UHMWPE is 1.76 × 10^?7mg/Nm, only 23.5% of wear rate of 0 kGy UHMWPE and 44.2% of wear rate of 100 kGy UHMWPE. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013