改性木薯淀粉/橡胶复合材料的制备及性能研究

以木薯淀粉、马来酸酐、苯乙烯为原料,过硫酸钾为引发剂,通过溶液共聚合成了一系列苯乙烯改性淀粉树脂(SMS)。然后将改性淀粉同丁苯橡胶(SBR)、天然橡胶(NR)进行混炼、硫化模压成型,制得苯乙烯改性淀粉/丁苯橡胶/天然橡胶复合材料。采用红外光谱(IR)对苯乙烯改性淀粉接枝共聚物进行了结构表征。通过拉伸性能测试考察了不同苯乙烯含量的木薯淀粉接枝产物对丁苯橡胶/天然橡胶的力学性能的影响。结果表明,淀粉改性后,随着苯乙烯含量的增多,所得复合橡胶的拉伸强度与邵氏硬度均呈现先增加后降低的趋势。当苯乙烯用量为15%时所制得的苯乙烯改性淀粉/丁苯橡胶/天然橡胶复合材料的拉伸强度与邵氏硬度最大且优于未改性淀粉复合材料,其拉伸强度为2.0MPa,邵氏硬度为25.8HD。     

氯化镁-乙醇络合物中乙醇的NMR定量研究

利用核磁氢谱技术对氯化镁-乙醇络合物中的乙醇进行定量分析研究,结果表明,采样时间和延迟时间的值对定量结果有一定的影响。以四氢呋喃为内标,将采样时间和延迟时间分别设定为4s和20s,利用核磁氢谱内标法测得氯化镁-乙醇络合物中乙醇的质量分数为55.40%,与热重法测定结果相符合。该方法测定结果的相对标准偏差为0.13%(n=6)。     

核磁共振波谱法测定聚环戊烯橡胶的微观结构

采用核磁共振波谱法对聚环戊烯橡胶进行一维氢谱和碳谱分析,结合二维核磁HSQC(Heteronuclear Single Quantum Coherence)方法,对聚环戊烯橡胶顺反异构体核磁谱峰进行归属。建立了聚环戊烯橡胶顺反异构体含量计算公式,根据该公式计算得到聚环戊烯橡胶顺反异构体含量。将本方法定量结果与红外法定量结果进行比对,结果显示,核磁共振波谱法更适合于聚环戊烯橡胶顺反异构体定量分析。     

固体核磁碳结构参数的修正及其在煤结构分析中的应用

为消除~(13)C CP/M AS/TOSS NM R测试中碳核NOE效应,获得相对准确的碳结构参数,考察了不同模型化合物的碳核NOE效应强度。结果表明,不同模型化合物碳谱分峰拟合的测试值与样品碳结构参数的理论值之间存在明显误差,其中,脂肪碳在25%-125%、芳香碳为4%-50%,NOE效应在固体核磁碳谱测试中影响显著。为此,将模型化合物脂肪碳和芳香碳的实测值和理论值进行回归分析,得到非线性回归方程。用该方程对9,10-二甲基蒽进行碳结构修正,发现修正后脂肪碳实测值与理论值之间误差由不修正时的119.60%减小至7.84%,芳香碳误差为由不修正时的-17.10%到1.11%,修正后误差均在10%以内;同时用该回归方程修正了不同煤的碳结构参数,发现不同煤未修正的H/C原子比与其元素分析H/C原子比误差在45%-53%,修正后误差只有4%-13%,与元素分析结果具有一致性,表明非线性回归方程能够方便、准确地消除固体核磁NOE效应,为煤中碳结构分析提供新的技术支撑。     

碳—碳键新型引发剂的研究

α-氰基苯乙酸乙酯用Cu~( )-TMEDA-O_2进行氧化偶联反应,产物经色谱或重结晶法分离,经红外光谱、紫外光谱、~1H核磁共振谱、质谱、元素分析鉴定及其碱性水解产物等认定为内消旋-2,3-二氰基-2,3-二苯基丁二酸二乙酯(Ⅰ).用Ⅰ引发苯乙烯进行本体聚合,测定了聚合温度和Ⅰ的用量对苯乙烯的转化率～时间曲线的影响,测定了各种条件下所得聚苯乙烯的分子量及其分散系数.1是一种既有效又安全的碳—碳键型引发剂.     

吸附法纯化蒲公英中黄酮类化合物的研究

蒲公英中黄酮类物质具有开发保健食品或药品的潜力。本文以苯乙烯和丙烯酰胺为单体、二乙烯苯为交联剂、甲苯为致孔剂,制备丙烯酰胺改性的大孔苯乙烯树脂。采用SEM与氮气吸附-脱附对其表征分析,并研究了其对蒲公英中黄酮类提取物的纯化和分离效果。结果表明黄酮的纯化率高达82.6%。最后,采用核磁氢谱、碳谱和红外手段对黄酮类物质中分离出的两个纯组分进行了分析,确定其为木犀草素和槲皮素。     

黄豆黄素纯度标准物质研制

建立黄豆黄素纯度标准物质的研制方法。选择纯度大于98%（质量分数）的黄豆黄素标准品作为标准物质候选物,通过加热和冷冻干燥去除多余的水分。通过红外、质谱、核磁氢谱进行结构确证和表征后分装,采用质量平衡法进行均匀性和稳定性检验。结果显示,标准物质均匀性良好,在常温条件下保存12个月稳定;采用质量平衡法和定量核磁法进行纯度定值,质量平衡法的定值结果为99.09%,定量核磁法的定值结果为99.13%,取平均值99.1%作为最终定值结果;对定值、均匀性和稳定性引入的不确定度进行了系统评定,扩展不确定度为0.3%(k=2)。研制的黄豆黄素纯度标准物质已申报国家一级标准物质,编号为GBW 10171。该标准物质可用于食品、保健品、饲料中黄豆黄素含量检测。     

基于固体分散剂制样的裂解/气相色谱-质谱联用定量测定PC/ABS共混物比例

建立了以二氧化硅为分散剂制样的裂解/气相色谱-质谱联用测定聚碳酸酯(PC)/丙烯腈-丁二烯-苯乙烯共聚物(ABS)共混物比例的分析方法。将样品冷冻破碎成粉末后,以二氧化硅为固体分散剂与样品混合后进样,在600℃裂解温度下裂解得到相应的裂解色谱图,选择PC/ABS共混物裂解色谱图上ABS的特征裂解产物——苯乙烯为定量峰,计算PC/ABS共混物中ABS的质量分数,再进一步推算PC的质量分数。以二氧化硅为固体分散剂制备系列已知含量的PC/ABS分散体,以ABS含量为横坐标,对应的苯乙烯峰面积为纵坐标绘制校准曲线,ABS在分散体中含量在0.06～20 g/kg(对应PC∶ABS=99.7∶0.30～0∶100)范围内的线性良好,相关系数(r~2)为0.994,以5倍信噪比(S/N=5)计算得到ABS的检出限为0.06 g/kg(对应的PC∶ABS比例为99.7∶0.30)。采用该方法对已知混合比例的PC/ABS样品进行测定,所得结果的回收率为95.3%～103%,相对标准偏差(RSDs,n=3)为1.1%～3.8%。该方法简便、准确度高,适用于PC/ABS共混物全范围比例的定量分析。     

电感耦合等离子体发射光谱测定钼铝合金中硅含量的方法研究

采用王水、氢氟酸在180℃加热条件下溶解试样,全面分析了硅元素的212.412、221.667、251.611、252.851、288.158 nm五条分析谱线的受干扰情况,最终选择了灵敏度和信噪比较高、受钼基体干扰程度较小的Si 288.158 nm为分析谱线。使用多谱线拟合(MSF)技术建立了Si 288.158 nm的光谱校正模型,通过校正模型对样品检测信号峰进行了校正,消除了基体钼(Mo 288.137 nm)的光谱干扰,建立了电感耦合等离子体发射光谱法(ICP-OES)测定钼铝合金中硅含量的方法。该方法在0.10～5.00 mg/L范围内(对应固体样品中硅的质量分数范围为0.010%～0.50%),硅的工作曲线线性关系良好,相关系数为0.9995;方法检出限和定量限分别为23μg/g和76μg/g;对3个不同含量的钼铝样品中的硅含量进行了测定,测定结果的相对标准偏差(RSD)在0.76%～1.36%之间,加标回收率在98.0%～106%范围,与标准(YS/T 1075.3-2015)中钼蓝分光光度法的测定结果一致。     

质量平衡法测定盐酸海洛因纯度

研究了盐酸海洛因纯度的定值技术。对经筛选的盐酸海洛因原料进行液相色谱–质谱、红外光谱、核磁及离子色谱定性分析,采用质量平衡法对盐酸海洛因原料进行纯度测定。在基于色谱的质量平衡法的基础上优化了检测条件,确定了主成分的含量,用卡尔费休法测定样品水分含量,最终得到盐酸海洛因纯度定值为95.1%。该分析结果的标准不确定度为0.32%。     

Preparation and properties of nanocomposites based on acrylonitrile–butadiene rubber,styrene–butadiene rubber,and polybutadiene rubber

Nanocomposites were prepared with different grades of nitrile rubber with acrylonitrile contents of 19, 34, and 50%, with styrene–butadiene rubber (23% styrene content), and with polybutadiene rubber with Na‐montmorillonite clay. The clay was modified with stearyl amine and was characterized by X‐ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and transmission electron microscopy (TEM). The XRD studies showed an increase in the gallery gap upon the modification of the filler by stearyl amine. The intercalation of the amine chains into the clay gallery gap was confirmed by the presence of some extra peaks (2928, 2846, and 1553 cm^?1) in the FTIR spectra. The clay–rubber nanocomposites were characterized by TEM and XRD. The mechanical properties were studied for all the compositions. An improvement in the mechanical properties with the degree of filler loading up to a certain level was observed. The changes in the mechanical properties, with changes in the nature and polarity of the rubbers, were explained with the help of XRD and TEM results. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1573–1585, 2004     

Difference in bound rubber formation of silica and carbon black with styrene‐butadiene rubber

Formation of bound rubber is affected by the physical structure and surface chemistry of filler and the property of rubber. Variation of the bound rubber formation in styrene‐butadiene rubber compounds filled with silica and/or carbon black was studied. Influence of temperature on extraction of loosely bound rubber was also investigated. For the both silica and carbon black‐filled compounds, the bound rubber content increases with increase in the silica content ratio. The bound rubber content decreases with increasing the extracting temperature. The loosely bound rubber content of the silica‐filled compound is higher than that of the carbon black‐filled one. Activation energy for the extraction of the unbound and loosely bound rubbers becomes higher as the total filler content increases. The activation energy of the silica‐filled compound is higher (almost double the value) than for the carbon black‐filled one. Copyright­© 2002 John Wiley & Sons, Ltd.     

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.     

Filler‐polymer interactions of styrene and butadiene units in silica‐filled styrene–butadiene rubber compounds

Styrene–butadiene rubber (SBR) is a copolymer of styrene and butadiene, and the butadiene unit is composed of cis‐1,4‐, trans‐1,4‐, and 1,2‐components. Filler‐polymer interactions of each component of SBR in silica‐filled SBR compounds were examined by microstructure analysis of the bound and unbound rubbers. The composition ratio of butadiene and styrene units (butadiene/styrene) of the bound rubber was higher than that of the compounded rubber. Of the butadiene units, the 1,2‐component of the bound rubber was more abundant than the cis‐1,4‐ and trans‐1,4‐components. The filler‐polymer interaction of the butadiene unit with silica was stronger than that of the styrene unit, and the interaction of the 1,2‐component was stronger as compared with the others. The butadiene–styrene ratio of the bound rubber of the compounds containing the silane coupling agent was lower than for the compounds without the silane. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 577–584, 2004     

聚氯乙烯表皮成分对加成型硅橡胶固化的影响

采用流变学方法研究了双组分加成型硅橡胶在不同聚氯乙烯(PVC)表皮上的固化动力学,并利用红外光谱、核磁共振波谱、电感耦合等离子体质谱仪等手段分析了PVC表皮成分,以确定导致双组分加成型硅橡胶不固化的具体原因。 结果表明,PVC表皮中导致硅橡胶不固化的主要元素为P元素。 在固定硅橡胶厚度为1 mm的情况下,当PVC表皮中的P元素质量分数低于3×10^-3%时,浇注在其上的双组分加成型硅橡胶依然能固化;而当PVC表皮中的P元素质量分数超过约2.4×10^-2%时,虽然浇注在其上的双组分加成型硅橡胶的中间层依然能固化,但与PVC表皮接触部分的硅橡胶不固化,且不固化层厚度随P元素质量分数增加而增加。 本文还研究了在P元素质量分数低于3×10^-3%的PVC表皮上,降低硅橡胶厚度至微米级时的固化行为,在P元素质量分数低于3×10^-3%的PVC表皮上,当硅橡胶厚度低于2 μm时,硅橡胶出现不完全固化现象。 双组分加成型硅橡胶在含有P元素的PVC表皮表面的固化行为主要是由硅橡胶样品中铂催化剂总含量及PVC表皮中的P元素含量确定的,同时也会受到双组分加成型硅橡胶反应速率以及铂催化剂、P元素在硅橡胶中的扩散速率的影响。     

Compatibilization level effects on the structure and mechanical properties of rubber‐modified polyamide‐6/clay nanocomposites

Exfoliated polyamide‐6 (PA6)/organically modified montmorillonite clay (OMMT) nanocomposites (PNs) were modified with partially maleinized styrene–ethylene/butadiene–styrene triblock copolymers (SEBS) at three maleinization levels in an attempt to link in these materials high toughness with appropriate small‐strain and fracture tensile properties. OMMT stayed only in the PA6 matrix, and no preferential location in the matrix/rubber interphase was observed. The increased dispersed phase size upon the addition of OMMT was attributed to interactions between maleic anhydride (MA) functionalized SEBS and the surfactant of OMMT. The rubber particle size generally decreased when the MA content of SEBS increased, and this indicated compatibilization. The subsequent good adhesion led to tough nanocomposites across a wide range of both strain rates and fracture modes. As the critical interparticle distance (τ_c) decreased with the MA content, and the other parameters that could influence the surface‐to‐surface mean interparticle distance did not change, it is proposed that in these PNs higher adhesion leads to a smaller τ_c value. Finally, the presence in the matrix of a nanostructured clay makes the rubber content necessary for the toughness jump to increase and τ_c to decrease. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3611–3620, 2005     

Evaluation of the polymer-solvent interaction parameter χ for the system cured styrene butadiene rubber and toluene

One of the most popular cured rubbers used in industrial applications is styrene butadiene rubber (SBR) and frequently its network structure is studied by means of swelling techniques in solvent. Normally, toluene is used as solvent in this test. In order to estimate the crosslink density from the equilibrium volume fraction of rubber in the swollen state, the correct evaluation of the Flory-Huggins interaction parameter χ is necessary. This work covers the swelling behavior of cured SBR in toluene. The rubber was vulcanized with different amounts sulfur and accelerator at 433 K in order to obtain several network structures and crosslink densities. Network characterisations of the compounds were made by swelling measurements in the frame of the Flory-Rehner relationship using the molecular weight of the network chain between chemical crosslinks obtained previously by mechanical tests. A relationship between χ and v_r, the polymer volume fraction at equilibrium (maximum) degree of swelling, was established for the cured SBR/toluene system. It was found that χ is not a constant but depends on the crosslink density in the sample. The types of crosslinks in these samples where estimated applying this function to the swelling behavior of the compounds previously treated with the thiol probe method.     

A SAXS and swelling study of cured natural rubber/styrene–butadiene rubber blends

A small‐angle X‐ray scattering (SAXS) and swelling study of natural rubber and styrene–butadiene rubber blends (NR/SBR) is presented. To this aim, specimens of NR and SBR and blends with 75/25, 50/50, and 25/75 NR/SBR ratios (in phr) were prepared at a cure temperature of 433 K and the optimum cure time (t₁₀₀). This time was obtained from rheometer torque curves. The system of cure used in the samples was sulfur/n‐t‐butyl‐2‐benzothiazole sulfenamide. From swelling tests of the cured samples, information about the molecular weight of the network chain between chemical crosslinks was obtained. For all cured compounds, in the Lorentz plots built from SAXS scattering curves, a maximum of the scattering vector q around 0.14 Å^?1 was observed. However, the q position shows a linear‐like shift toward lower values when the SBR content in the SBR/NR blend increases. In pure NR or SBR the q values show a different tendency. The results obtained are discussed in terms of the existence of different levels of vulcanization for each single phase forming the blend and the existence of a third level of vulcanization located in the interfacial NR/SBR layer. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 2320–2327, 2009     

苯乙烯-异戊二烯-丁二烯三元集成橡胶的合成、表征及性能研究

以正丁基锂为引发剂、环己烷-己烷混合溶剂为溶剂,采用二元结构调节剂,对S-SIBR(溶液苯乙烯-异戊二烯-丁二烯共聚物)三元共聚进行了研究,考察了不同单体含量,以及苯乙烯微嵌段含量对SIBR性能的影响.在500 L全流程中试装置中采用湿法充油技术批量制备了充油型集成橡胶,对充油集成橡胶的结构、性能以及在轮胎中的应用进行了研究.结果表明,充油型SIBR的混炼行为、硫化速度、机械性能、滚动损失及抗湿滑性能均较优异,机械性能完全符合轮胎胎面胶的性能要求,并且具有优异的抗湿滑性和滚动阻力,是一种理想的轮胎胎面材料.     

气相色谱-质谱联用法测定橡胶制品中多环芳烃（蒽）含量不确定度评定

目的对气相色谱-质谱联用仪法测定橡胶制品中多环芳烃（蒽）含量不确定度进行评定,确定影响不确定度的关键因素。方法依据《ZEK01.4-2008 GS认证过程中PAHs的测试和验证》,使用气相色谱-质谱联用仪法测定橡胶制品中多环芳烃（蒽）含量,并对结果的不确定度进行评定,分析影响测量不确定度的各个因素,对各个分量进行计算和合成。结果扩展不确定度U=5.7 mg/kg,置信概率95%。结论该实验的不确定度主要影响因素是曲线校准。