充油溶聚丁苯橡胶2564 A的微观结构与性能

研究了溶聚丁苯橡胶(SSBR,牌号为2564 A)的微观结构与性能,并与牌号为5025-2的SSBR及乳聚丁苯橡胶(ESBR,牌号为1712)进行了对比。结果表明,与ESBR 1712相比,SSBR 2564 A生胶的数均分子量和重均分子量大,分子量分布窄,乙烯基和顺式结构含量高、反式结构含量低,混炼胶的硫化速率慢,硫化胶的物理机械性能略差,耐老化性能、压缩生热性能及炭黑分散性优;与SSBR 5025-2相比,SSBR 2564 A生胶的数均分子量、重均分子量及分子量分布相当,乙烯基含量高,顺式结构含量略高,反式结构含量低,混炼胶的结合胶含量高,交联密度相当,硫化速率略快,硫化胶的物理机械性能相当,耐老化性能优,压缩生热性能及炭黑分散性相当。     

含氨基和羧基POSS/聚合物复合材料鞣制性能

以笼型八乙烯基倍半硅氧烷(POSS-Vi)、丙烯酰胺(AM)和甲基丙烯酸(MAA)为原料,通过自由基聚合法制备含氨基、羧基的POSS/聚合物复合材料P(POSS-AM-MAA)。采用FTIR、XRD、TEM等对P(POSS-AM-MAA)的结构和形貌进行表征。结果表明：复合材料P(POSS-AM-MAA)是具有立方笼型结构的POSS外围被聚合物链段包覆的材料。将复合材料P(POSS-AM-MAA)配合占酸皮重的4%戊二醛应用于山羊酸皮鞣制工艺中,考察了氨基含量、相对分子质量(简称分子量)大小、复合材料用量等对坯革性能的影响。结果表明：当复合材料P(POSS-AM-MAA)中氨基含量为433 μmol/g、数均分子量为27237,其用量为酸皮重的8%,结合pH为8.5时,结合鞣坯革收缩温度为83.7 ℃,增厚率为107.3%,相较于单独戊二醛鞣制坯革均有所提高;结合鞣坯革中的游离甲醛含量为28.3 mg/kg;结合鞣坯革的抗张强度为16.5 MPa,断裂伸长率为109.5%,撕裂强度为58.8N/mm,与戊二醛鞣制坯革相当。     

重过磷酸钙中游离磷酸的分析方法

<正> 一.前言我国对重过磷酸钙(以下简称重钙)中游离磷酸含量的测定,是在对普通过磷酸钙(简称普钙)中游离酸含量测定的分析方法基础上稍加改进发展起来的。参阅世界各国的重钙标准,除苏联的ΓОСТ16306-80标准中Б级规定的游离磷酸含量和我国现行标准规格接近之外,其它各国如美国、印度、土耳其、突尼斯和巴基斯坦等国标准规格中的游离磷酸含量均     

超高分子量聚丙烯酰胺的辐射合成技术研究

采用丙烯酰胺(AM)和丙烯酸(AA)为主体单体,次磷酸钠为链转移剂,通过⁽⁶⁰⁾Co-γ射线辐射引发,制备阴离子聚丙烯酰胺(APAM),研究了链转移剂含量、吸收剂量、剂量率对APAM分子量的影响。结果表明,APAM的分子量与吸收剂量呈正相关,而与链转移剂含量呈负相关。在丙烯酰胺∶丙烯酸=180∶60,单体浓度为30%,次磷酸钠为0.15‰,吸收剂量为300 Gy,剂量率为25 Gy/h的条件下,得到的APAM黏均分子量为2.93×10(60)Co-γ射线辐射引发,制备阴离子聚丙烯酰胺(APAM),研究了链转移剂含量、吸收剂量、剂量率对APAM分子量的影响。结果表明,APAM的分子量与吸收剂量呈正相关,而与链转移剂含量呈负相关。在丙烯酰胺∶丙烯酸=180∶60,单体浓度为30%,次磷酸钠为0.15‰,吸收剂量为300 Gy,剂量率为25 Gy/h的条件下,得到的APAM黏均分子量为2.93×10⁷。在气动旋转反应釜中,剂量率为257。在气动旋转反应釜中,剂量率为25⁴0 Gy/h,吸收剂量为12540 Gy/h,吸收剂量为125²00 Gy,合成的APAM分子量基本相同,最高可达2.88×10200 Gy,合成的APAM分子量基本相同,最高可达2.88×10⁷,且残留单体含量(干基)为0.01%。     

超高分子量聚丙烯酰胺的辐射合成技术研究

采用丙烯酰胺(AM)和丙烯酸(AA)为主体单体,次磷酸钠为链转移剂,通过~(60)Co-γ射线辐射引发,制备阴离子聚丙烯酰胺(APAM),研究了链转移剂含量、吸收剂量、剂量率对APAM分子量的影响。结果表明,APAM的分子量与吸收剂量呈正相关,而与链转移剂含量呈负相关。在丙烯酰胺∶丙烯酸=180∶60,单体浓度为30%,次磷酸钠为0.15‰,吸收剂量为300 Gy,剂量率为25 Gy/h的条件下,得到的APAM黏均分子量为2.93×10~7。在气动旋转反应釜中,剂量率为25~40 Gy/h,吸收剂量为125~200 Gy,合成的APAM分子量基本相同,最高可达2.88×10~7,且残留单体含量(干基)为0.01%。     

均相法制备生物柴油的研究

研究了添加四氢呋喃(THF)为共溶剂酸催化一步法酯交换制备生物柴油的实验过程,考察了醇油比、THF的添加量、原料中水及游离酸含量对反应的影响.结果表明,随着醇油摩尔比或THF的加量增大,转化率、收率均增大,酸价降低,最佳醇油摩尔比为21:1,最佳THF的添加质量分数为35%;原料中的水含量对于酯交换反应的副作用较大,随着水含量的增大,转化率明显降低、酸价升高,水质量分数达到1.6%以后转化率低于90%;原料中游离酸含量对反应过程影响较小,游离酸含量增大,转化率和酸价均略有增大.     

不同分子量的PEI对乙烯基酯树脂力学性能的影响

制备了4种分子量不同的刚性聚醚酰亚胺齐聚物(PEI),研究了不同分子量的PEI改性乙烯基酯树脂对其固化物力学性能的影响.结果表明:分子量不同的PEI在最佳含量改性乙烯基酯树脂固化物时弯曲强度变化不大,均在105MPa左右;冲击韧性则有大幅度的提高,其中当PEI相对分子质量为1373.1,特性黏度为5.3dL/g,质量含量占15%时,冲击韧性达到16.8kJ/m2,约为未改性树脂(冲击韧性为3.8kJ/m2)的5倍.     

脱色猪血红蛋白酶解产物制备及其抗氧化性

通过复合蛋白酶(Pancreatin and Protamex)酶解制备了猪血红蛋白酶解产物,将其产物采用活性炭吸附脱色.酶解产物的分子量范围在＞15 kDa～＜1 kDa(游离氨基酸)之间,脱色酶解产物的分子量范围大部分＜5 kDa.脱色祛除94.36%的高铁血红素从而改善终产物的色泽.酶解产物及脱色产物具有还原力和DPPH自由基清除能力.猪血红蛋白酶解产物的抗氧化活性依赖于其分子量和氨基酸组成.     

离子交换色谱法测定注射用双黄连(冻干)中氨基酸的含量

应用氨基酸自动分析仪,采用离子交换色谱-柱后衍生化法,测定注射用双黄连(冻干)样品、中间体及其药材中游离和水解后的氨基酸的含量。结果显示,注射用双黄连(冻干)成品3批样品中游离氨基酸含量分别为0.46%,0.38%,0.37%,总氨基酸含量分别为1.30%,1.40%,1.20%;金银花中间体中游离氨基酸和总氨基酸含量分别为1.07%和3.36%,黄芩中间体中游离氨基酸和总氨基酸含量分别为0.01%和0.1%,连翘中间体中游离氨基酸和总氨基酸含量分别为0.05%⁰.85%;金银花药材中游离氨基酸和总氨基酸含量分别为0.88%和9.40%,黄芩药材中游离氨基酸和总氨基酸含量分别为0.26%和4.73%,连翘药材中游离氨基酸和总氨基酸含量分别为2.83%和5.86%,该实验结果为注射用双黄连(冻干)质量标准的提高提供了参考依据。     

异氰酸酯预聚物的游离单体含量与分子量分布

阐述异氰酸酯预聚物游离单体的产生原因 ,提出游离单体含量与分子量分布的关联性 ,采用新的聚合方法和后处理工艺 ,得到具有实用价值的高性能异氰酸酯预聚物。     

Modelling of resole type phenol formaldehyde polymerization

The kinetics of polymerization of phenol formaldehyde has been modelled to account for the formation of highly-branched resole molecules. The conversions of phenol and formaldehyde, number-average chain length, degree of branching and the concentrations of internal and external ortho and para-H atoms are obtained as functions of time, for several values of the various rate constants and the initial phenol to formaldehyde ratios. The conversions of phenol and formaldehyde are found to be most sensitive to the rate constant associated with the reaction between the external para-H atom with ---CH₂OH groups. The condensation between two ---CH₂OH groups prevents complete depletion of formaldehyde and leads to highly-branched, high molecular weight final products at large reaction times. Our studies show that at low values of the initial phenol to formaldehyde ratio, small amounts of lightly-branched, low molecular weight polymer with a high degree of substitution by ---CH₂OH groups is obtained. At some intermediate initial phenol to formaldehyde ratio, highly-branched, high molecular weight product is obtained and at high values of this feed ratio, larger amounts of lightly-branched, lower average molecular-weight product is obtained.     

多聚甲醛与苯酚物质的量比对可发性甲阶酚醛树脂性能的影响

采用多聚甲醛代替37%的甲醛溶液,在20%NaOH水溶液催化下与苯酚逐步加成聚合,合成了可发性甲阶酚醛树脂。研究了多聚甲醛与苯酚物质的量比(F/P)对合成树脂固含量、粘度、游离苯酚、游离甲醛、凝胶时间、分子结构、分子质量、树脂热性能及泡沫性能的影响。结果表明,F/P值为1.8时,可得到性能优良成本较低的可发性甲阶酚醛树脂,树脂粘度1.4 Pa.s,游离甲醛质量分数1.17%,游离苯酚质量分数6.72%,羟甲基指数1.41,树脂分子质量在240左右,耐热性较好。     

Molecular size and solvation of low molecular weight poly(ethylene oxide) and phenol–formaldehyde resols in different solvents

Several solvent systems are presently used to characterize the molecular weight of phenol–for-maldehyde resins. However, results reported in the literature for different molecular weights may not be representative of true molecular weight, but rather may be distorted by aggregation and solvation. In this report an effort to clarify this situation was conducted, first by using a suitable calibration with poly(ethylene glycol) and then using this polymer as a molecular size standard to determine the size of phenol–formaldehyde oligomers in solution. In the calculation of the molecular sizes of phenol–formaldehyde resols, proper accounting of the variation of the Mark–Houwink parameters with molecular weight for low degrees of polymerization must be made for poly(ethylene glycol). The Mark–Houwink constants for poly(ethylene glycol) are very similar in presence or absence of salts, and are considered to be unaffected by solution ionic strength. It is not the case for phenol–formaldehyde, whose apparent molecular size varies with the nature of the solvent. The actual molecular weight and molecular dimension distribution are discussed for different type A resols used as adhesives in the wood composite industry.     

Phenolic resol resin from phenolated corn bran and its characteristics

To prepare phenolic resol resin, corn bran (CB) was liquefied in the presence of phenol and the liquefied CB was condensed with formaldehyde under alkaline condition. From NMR spectra of phenolated CB and phenolated CB–based resol resin, it was found that phenol was reacted with depolymerized CB components and the phenolated CB was methylolated by condensation with formaldehyde. Molecular weight distribution was divided into a high molecular weight zone, attributed mainly to phenolated CB, and a low molecular weight zone, which was attributed to the condensation reactants of formaldehyde and the unreacted phenol of liquefied CB. When reaction conditions became severe, a high molecular weight zone was increased. Formaldehyde/unreacted phenol of liquefied CB molar ratio most affected the change of a low molecular weight zone. To reduce the viscosity of the phenolated CB–based resol resin, a milder condensation condition was required compared with that for preparing the conventional resol resin. Properties of the resol resin were comparable to those of conventional resol resin for plywood manufacture. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1365–1370, 2003     

Phenolic resol resin adhesives prepared from alkali-catalyzed liquefied phenolated wood and used to bond hardwood

Wood-based resol resins were prepared from both water- and sodium hydroxide (NaOH)-catalyzed liquefied phenolated wood. The effects of various reaction parameters, e.g. the concentrations of phenol and formaldehyde, temperature, and time, on the extent of yield, free phenol content, molecular weight as well as the gluability of the resol resins have been evaluated. As far as the yield, free phenol content, and molecular weight are concerned, the optimum conditions of resol resin preparation were found to be a phenol : wood weight ratio of 4 : 6, a formaldehyde : phenol mole ratio of 1.5 : 1, a temperature of 82.5°C, and time 3 h. However, these optimum conditions changed when the performance of the adhesives was considered in terms of the adhesive bond strengths for plywood joints. The yield, molecular weights, polydispersity, and gluability of resol resins prepared from water-catalyzed liquefied wood were lower compared with those prepared from NaOH-catalyzed ones. In most cases, the dry-bond strengths of the experimental plywood joints exceeded the minimum Japan Agricultural Standard (JAS) values. On the other hand, except at a higher formaldehyde: phenol ratio (i.e. 2.0 : 1 mole ratio), the plywood joints of all samples delaminated during 'boil-dry-boil' cyclic treatments. However, both dry- and wet-bond strengths of the plywood joints could be improved to exceed standard values by using an additional crosslinking agent, e.g. poly(methylene (polyphenyl isocyanate)) (polymeric MDI). The adhesive perfomance of the wood-based resol resins was explained on the basis of the adhesion between wood veneers and resol resin adhesives.     

Modelling of resol resin polymerization with various formaldehyde/phenol molar ratios

The kinetics of polymerization of phenol and formaldehyde are modelled to account for the formation of resol resin with various initial formaldehyde/phenol molar ratios. The conversion of phenol and formaldehyde is used to determine the equilibrium constants for phenolate ion and methylene glycol. The relative concentration of each compound is obtained as a function of time. The molecular weight is also determined for each resol resin at the end of the reaction. The evaluation of substituted phenols, hydroxymethylol phenols and methylene bridges was carried out by infrared spectroscopy. The experimental tendencies are in agreement with the results of the model. © 2001 Society of Chemical Industry     

Statistical aspects for the production of novolacs

Statistical parameters for the phenol (P)-formaldehyde (F) condensation under acid conditions are derived in the frame of Flory-Stockmayer's theory. Phenol is assigned an average functionality f = 2.31 as proposed by Drumm and Le Blanc (1972). Results show that a molar ratio $\text{(}\text{F}\text{P}\text{) = 0.881}$ leads to gelation at full formaldehyde conversion. Free phenol and number and weight average molecular weights are calculated, showing a significant dependence on the final formaldehyde conversion and the selected molar ratio (F/P). A good agreement between theoretical predictions and experimental results is obtained.     

麦草碱木素酚化改性及其制备LPF胶粘剂工艺研究

利用碱性条件下酚化改性的麦草碱木素代替部分苯酚制备了高木质素/苯酚比例和胶粘强度高的木质素酚醛树脂(LPF)胶粘剂.利用傅立叶红外光谱(FT-IR)和凝胶色谱(GPC)研究了麦草碱木素在碱性条件下酚化改性前后的结构变化.FT-IR分析表明,麦草碱木素发生了酚化反应,伴随着酯基的断裂和甲氧基的脱落;GPC结果显示,木质素平均分子量降低,分子量分布范围变宽.接着,研究了木质素/苯酚比例、氢氧化钠浓度、甲醛/木质素比例、酚化温度、酚化时间、缩聚温度、缩聚时间等反应工艺参数对LPF胶粘剂性能的影响,优化了麦草碱木素酚化改性制备LPF胶粘剂的反应工艺参数.最后,比较了反应工艺参数优化的LPF胶粘剂与传统PF胶粘剂的各项性能,结果显示,麦草碱木素酚化改性后代替70 % 的苯酚制备得到的LPF胶粘剂的胶粘强度与传统PF胶粘剂相近.     

A study on composites from phenol‐formaldehyde‐casein resin

A modified phenol‐formaldehyde (PF) resin was synthesized under alkaline condition in varying proportion of casein up to 20% (w/w) of phenol. All the prepared resins were characterized by free phenol content, free formaldehyde content, viscosity measurements, number average molecular weight determination by conductometry and Infrared Spectroscopy (IR). Their curing kinetics was studied isothermally and by differential scanning calorimetry (DSC) on dynamic runs. The resin samples were cured using concentrated hydrochloric acid and hexamine individually. Cured resins were characterized by IR and Thermogravimetry (TGA). Glass fabric reinforced composites (GFRC) were fabricated by maintaining 40 : 60 proportion of resin to reinforcement material. The laminates thus formed were characterized for their mechanical properties and chemical resistance. Enhancements in thermal stability of the resin as well as toughness of composite with increase in casein content were observed for the resins studied. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

高软化点低游离酚热塑性酚醛树脂的合成与表征

通过单因素实验,考察了影响制备高软化点热塑性酚醛树脂软化点、收率和树脂中游离酚的因素,并获得了优化的配方和工艺条件.结果表明,在苯酚与甲醛的物质的量之比为1∶0.9、催化剂为草酸、催化剂用量为1％(按苯酚的质量计算)、反应温度为90℃、反应时间为6h的条件下,所制备的线性酚醛树脂为无色透明、光泽度好的固体,软化点为12...