间-甲粘合体系在斜交轮胎中的应用

试验研究间-甲粘合体系在斜交轮胎缓冲层和外层帘布胶中的应用.结果表明,在斜交轮胎缓冲胶和外层帘布胶中加入间-甲粘合体系,可以明显提高硫化胶的粘合性能,对物理性能影响不大;能够提高成品轮胎的耐久性能、速度性能及帘布层间粘合强度,减少帘布层脱层问题.     

间-甲-白粘合体系在载重汽车轮胎缓冲层胶中的应用

探讨间-甲-白粘合体系中的间苯二酚给予体R-80和亚甲基给予体HMT对载重汽车轮胎缓冲层胶性能的影响。通过对试验数据进行回归分析,并根据回归方程做出等高线图,直观地探讨了间苯二酚给予体R-80和亚甲基给予体HMT用量对缓冲层胶的帘线抽出性能、焦烧时间、正硫化时间、定伸应力、拉伸强度、拉断伸长率和撕裂强度的影响。     

Dissolution of Ethylenediamine Pretreated Pulp with High Lignin Content in LiCl/DMSO without Milling

Abstract

Various hardwood and softwood chemical pulps, including those with relatively high lignin content (up to ca. 10.5%), were completely dissolved without milling in lithium chloride/dimethyl sulfoxide (LiCl/DMSO) after a pretreatment with ethylenediamine (EDA). Because milling of the sample is not required, degradation of the cell wall components caused by milling does not take place. After the EDA pretreatment, the crystallinity of the pulps remained as high as the original pulps, although the crystal structure changed. This is the first time that transparent solutions of underivatized pulps with high lignin content were obtained in a simple organic solvent system. Interestingly, even in the case of coarse wood meal (40–80 mesh) about 70% could be dissolved after repeating the dissolving procedure two times. The formation of a pulp–EDA or wood–EDA complex seems to be critical for the dissolution in LiCl/DMSO. The nuclear magnetic resonance (NMR) spectrum of the EDA treated pulp solution had good resolution even though the degree of polymerization (DP) of the cellulose in the pulp is very high.     

Fractionation and Characterization of Wood Cell Wall Components of Fagus crenata Blume Using LiCl/DMSO Solvent System

Abstract

The fractionation of wood cell wall components was achieved by the application of the LiCl/DMSO solvent system developed in our previous study. Various soluble and insoluble fractions were prepared from beech milled wood by extractions with DMSO containing different amounts of lithium chloride (LiCl) for the study of a lignin-carbohydrate complex (LCC). Nitrobenzene oxidation (NO) analyses demonstrated that the lignin in the soluble fractions always has lower yields of NO products consisting of syringaldehyde + syringic acid (S_y) and vanillin + vanillic acid (V_a). The syringyl ratios, S_y/(S_y+V_a), were also lower than in insoluble fractions. Accordingly, lignins with lower syringyl ratios are better soluble than those with higher syringyl ratios. The former is typical in the primary wall and the latter in the secondary wall. Solubilization of glucan is significantly dependent on the LiCl concentration in DMSO. In the absence of LiCl, only about 6% of glucan was found in the soluble fraction, but about 40% of lignin and xylan were solubilized. The additional 40% of lignin and xylan became soluble together with glucan solubilization, which increased at 3% LiCl concentration. However, a fraction amounting to 13% (based on the whole wood) still remained as a residue under these conditions. Glucan solubilization could not be the reason for this observation as ball-milled cellulose is soluble in 3% LiCl/DMSO. It is likely that strong interactions between lignin and carbohydrates prevent solubilization of this fraction, which has never been isolated and analyzed in previous studies.     

-乳酸的研究

从所选取的产l-乳酸的4株菌中筛选出一株性能优良、糖利用率和乳酸产量较高的菌种作为试验用菌种。对影响乳酸菌发酵大豆秸秆酶解物制备l-乳酸的因素进行了研究,影响大豆秸秆酶解液发酵的主要因素是菌种类型、底物糖浓度、接种量、温度及pH值。结果表明:干酪乳酸菌是较适宜的发酵菌种,较适宜的发酵条件为:发酵温度30℃,接种量10%,pH值5.5。随着底物糖含量的增加,乳酸产率相应增大,在实验范围内,乳酸菌发酵所产乳酸的产率达到80%。     

氨预处理对大豆秸秆纤维素酶解产糖影响的研究

为了提高大豆秸秆酶解产糖能力, 以利于从大豆秸秆中提取生物降解性塑料的原料 ?? 乳酸, 对大豆秸秆纤维素预处理过程的影响因素进行了探索,对预处理前后大豆秸秆的物理结构变化、化学成分变化及预处理条件对大豆秸秆酶水解产糖的影响进行了研究。研究结果表明,粉碎结合氨处理对大豆秸秆酶水解影响较大,较适宜的预处理条件为大豆秸秆粉碎至 140 目,10%氨水处理 24h。经过预处理后大豆秸秆纤维素含量提高 70.27%, 半纤维素含量下降 41.45%, 木质素含量下降 30.16%, 有利于大豆秸秆酶解产糖。     

DMSO as solvent on the synthesis of flame-retardant polyether polyols

Polyether polyols with flame-retardant properties are synthesized using glycerol phosphate disodium salt as an initiator and dimethyl sulfoxide (DMSO) as a solvent. The molecular weight of the polyol decreased when higher solvent to initiator ratios were used, revealing that a larger amount of salt was activated. In addition, the larger the amount of activated salt was, the higher the percentage of phosphorous was in the final polyol. Glycerol phosphate disodium salt was still partially insoluble in the studied proportions of DMSO. Thus, the recovery and reuse of this part of the salt for the synthesis of new flame-retardant polyols were evaluated. The recovered salt promoted a shorter induction period because it presented a larger amount of deprotonated hydroxyl groups. In addition, there were no differences between both synthesized polyols, indicating that it is possible to use the recovered salt in the same way as it is used commercially with the advantage of a shorter induction period for polymerization. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47042.     

Investigation of dispersion states and rheological properties of SPI in the DMSO/urea

Dimethylsulfoxide (DMSO)/urea were chosen as a hybrid solvent system to dissolve soy protein. The dispersion status and rheological properties of soy protein isolates (SPI) in the DMSO/urea were studied. The result showed that SPI has relatively high solubility in DMSO/urea blend system and urea served as a key factor of dissolving SPI in the system. SPI in the DMSO/urea hybrid system exhibited different dispersion statuses with increasing of SPI content. The SPI dispersions in the DMSO/urea presented shear thinning or pseudoplastic behavior. The pseudoplastic behavior, the degree of non‐Newtonian flow and the extent of structuralization of SPI dispersion system with increasing SPI content were discussed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008.     

PAN／DMSO溶液凝胶化行为的流变学研究

通过动态流变测试,研究PAN／DMSO溶液的热致变凝胶化过程和测定PAN／DMSO溶液的凝胶点温度。主要通过测量动态流变学参数（动态模量G′i和G″ii、损耗角正切tanδ、复数粘度η^＊）来表征PAN溶液的凝胶化行为,分析了含水量对溶液凝胶化行为和凝胶结构的影响。结果发现,虽然PAN溶液的凝胶点温度随着溶液中含水量的增加而升高,但是由松弛指数n和分形维数值df表征的凝胶结构几乎不受溶液中含水量的影响。     

Separation and Structural Characterization of Lignin from Hybrid Poplar Based on Complete Dissolution in DMSO/LiCl

In this paper, the physicochemical properties and structural features of six lignin preparations separated with a total dissolution of ball-milled wood in dimethyl sulfoxide and lithium chloride (DMSO/LiCl) followed by extraction with ethanol/water were investigated. These isolated lignin fractions were characterized using wet chemical analysis, FT-IR, and ¹H and¹³C-NMR techniques. Experimental results showed that separated lignin preparations were relatively free of associated polysaccharides. These lignin fractions were classified as guaiacyl-syringyl lignin type: mainly composed of guaiacyl units with noticeable amounts of syringyl units and fewer p-hydroxyphenyl units. The molar ratio of non-condensed guaiacyl units to syringyl units (G/S) decreased as the ratio of LiCl to poplar weight increased. The results also showed that these lignin preparations consisted mainly of β-O-4 ether bonds combined with small quantities of β-β′ and β-5 carbon-carbon linkages. Furthermore, considerable amounts of esterified p-hydroxybenzoic acids and minor amounts of esterified p-coumaric acid were also detected in these lignin fractions.     

Ultrafine cellulose triacetate mats electrospun by using co‐solvent of DMSO/chloroform system

Cellulose triacetate (CTA) nanofiber nonwoven mats were continuously electrospun by using mixed solvent of DMSO/chloroform system. The size and morphology of CTA nanofibers were investigated. It was found that CTA fibers with diameters in the range of 98 nm–1.81 μm were obtained from 8 wt % CTA solutions in 1 : 1, 3 : 2, 2 : 1, 3 : 1, 5 : 1 and 7 : 1 (v/v) DMSO/chloroform. The average diameter of CTA nanofiber was decreased and size distribution was narrowed with increasing the DMSO content in the mixed solvent. Smooth and uniform nanofibers with mean diameters of about 260 nm could be obtained from a solution of CTA in the binary system DMSO/chloroform 5 : 1(v/v) at a polymer concentration of 8 wt %. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40373.     

百菌清对麦秸秆／PP复合材料耐腐蚀性能的影响

研究了百菌清作为抗菌剂对麦秸秆／PP复合材料耐腐蚀性能的影响,制备5种百菌清含量的麦秸秆／PP复合材料,参照ASTMG21—96对复合材料进行腐蚀实验,并测试腐蚀后麦秸秆／PP复合材料的力学性能、吸水性能、色差以及表面微观结构。结果表明：百菌清添加量为1．25％时,腐蚀后麦秸秆／PP复合材料的综合性能较好,与不添加抗菌剂的复合材料相比,弯曲强度、弯曲弹性模量、拉伸强度、冲击强度分别提高了13．71％,54．91％,10．46％,47．53％,吸水192h的吸水率降低了23．69％,腐蚀前后色差值则减小了11．56。