耐水性大豆基木材胶粘剂两步法工艺研究

利用天然高分子聚合物开发无甲醛木材胶粘剂是人类社会发展的必然选择.在国际上,利用低温大豆粕制备生物质基木材胶粘剂具有相当长的历史.但是在传统豆胶制备方法中,碱等变性剂用量高达豆粕干重的6%～7%或更高,外加4%左右的石灰乳.豆胶中残碱对大豆蛋白的水解破坏难以得到控制,因此传统豆胶都不属于耐水胶粘剂.在本研究中,采用低碱量低液比高强度变性和均质处理分两段进行的工艺技术解决了这一矛盾.得到了制备符合国标Ⅱ类(耐热水)的大豆基木材胶粘剂的主要工艺参数并通过验证试验加以确定.最后把新法豆胶优化工艺与两个典型的传统豆胶制作配方做了比较.这种豆胶制备新工艺具有国际先进水平.     

木材工业用大豆蛋白胶粘剂研究与应用现状

随着木材工业持续快速发展和化石资源的日益枯竭,寻找绿色环保、可再生的木材用胶粘剂已经成木材工业面临的重大课题。从大豆蛋白胶粘剂的产生、发展,大豆蛋白的结构、特性、耐水改性机理、改性方法等几个方面,综述了近年来木材用大豆蛋白胶粘剂的研究进展和发展趋势。     

蛋白改性技术在大豆蛋白基木材胶粘剂制备中的应用

在建设环境友好型和资源节约型社会的今天,三醛胶面临的问题日益严峻,开发新型环保、绿色胶粘剂已成为趋势。而通过改性技术制备的大豆蛋白基木材胶粘剂具有很好的应用前景。本文综述了胶粘剂制备中大豆蛋白改性的原理及各种改性技术的研究现状,并分析了目前研究中存在的问题和今后的研究重点。     

大豆蛋白乳液胶粘剂改性的研究

由于以石化原料合成的胶粘剂在生产和使用过程中会对环境带来不良影响,近年来采用可再生资源,如大豆蛋白合成环保胶粘剂已成为趋势.以尿素和亚硫酸钠改性大豆蛋白,与醋酸乙烯酯等复合单体在过硫酸铵引发下进行接枝共聚,合成了醋酸乙烯醣一大豆蛋白接枝共聚乳液胶粘剂.并通过金属盐、聚合物树脂、异氰酸酯、偶联剂与乳液共混改性的方法,研究了不同改性剂对乳液胶粘剂性能的影响.结果表明:采用金属盐改性制备的乳液胶粘剂具有良好的综合性能;异氰酸酯则应溶解于适当溶剂或使用其加成产物,以延长胶粘剂的适用期.     

乙醇改性大豆蛋白制豆胶的研究

研究乙醇改性大豆蛋白对木材用豆胶的胶粘性能的影响.乙醇可使大豆蛋白发生部分变性,使蛋白分子中疏水性基团暴露出来,以提高豆胶的耐水性.通过正交试验优化出最佳条件:乙醇浓度30%,蛋白与水质量比1:9、改性时间45 min、改性温度75℃.将上述最佳条件下制得的豆胶施在胡桃木样品上,经三个循环的48 h水浸泡和48 h空气干燥后剪切强度由未浸泡前的81.6 MPa降至73.9 MPa,仅下降了9.4%.结果表明:乙醇改性后的豆胶的粘接强度和耐水性都有所提高.     

戊二醛改性提高大豆胶粘剂耐水性能

以脱脂大豆粉(SF)为原料,选用十二烷基硫酸钠(SDS)和戊二醛(GA)作为改性试剂,制备出具有较好耐水性能的木材用胶粘剂,并应用于杨木胶合板,分别研究了pH值、戊二醛用量、反应时间以及最终改性胶粘剂贮存时间对耐水胶合性能及表观粘度的影响,并采用十二烷基硫酸钠.聚丙烯酰胺凝胶电泳(SDS-PAGE)和傅屯叶变换红外光谱(FT-IR)分析手段探讨了改性胶粘剂耐水性能增强机理.结果表明:较佳合成工艺为:pH值为12.0,GA添加量0.80wt%(基于脱脂豆粉质量),反应时间1.0 h,反应温度30.0℃.按照GB/T 9846-2004胶合板中Ⅱ类板标准检测,耐水胶合强度可达0.68MPa.SDS-PAGE谱图说明蛋白质分子间形成化学键交联,FT-IR分析表明有环状吡啶结构生成,这些可能是改性胶粘剂耐水性能提高的原因.     

国内大豆胶粘剂的改性研究进展

大豆胶粘剂是一种绿色环保胶粘剂,在人造板领域具有很大的应用潜力.为改善大豆胶黏剂的耐水胶合性能及防腐性能,人们进行了大量的改性研究,其中耐水胶合性能的改性研究较多,包括物理改性、尿素改性、酸碱盐改性、接枝共聚、共混改性、有机试剂改性、晶须、纳米改性等.该文对目前国内有关大豆胶粘剂的改性研究进展进行了综述.     

花生荚果先豆、基豆脂肪酸含量分析

选用花育22号、丰花1号、10L4、09S2、09S8和FB4等6个花生材料,每份材料各8个双仁荚果测定了其先豆、基豆脂肪酸含量。全部参试材料亚油酸含量均值均为基豆高于先豆,其中丰花1号和10L4先豆与基豆间差异达极显著水平;二十四碳烷酸含量均值均为先豆高于基豆,其中09S8和10L4先豆、基豆间差异显著,丰花1号和FB4先豆、基豆间差异达极显著;其他脂肪酸含量先豆、基豆间无明显规律。     

豆基婴幼儿配方粉的研究进展

为促进我国豆基婴幼儿配方粉的生产,从大豆分离蛋白、其他营养物及相关法规等方面介绍了国内外豆基婴幼儿配方粉的发展史及研究现状.并从大豆致敏原的分类及主要致敏原、异黄酮在婴幼儿体内的代谢、吸收以及毒性水平等角度分析了豆基婴幼儿配方粉的安全问题.同时提出采用合适的脱敏技术可以提高豆基婴幼儿配方粉的安全性.     

廊豆6号大豆新品种的选育及栽培技术要点

大豆新品种廊豆6号是河北省廊坊市农林科学院在2002年以科丰6做母本，豫豆22做父本，进行品种间杂交选育而成的。具有高产、优质、抗病和抗逆性强等特点，区域试验较对照品种中黄13增产9.29%，生产试验增产11.0%；粗蛋白质（干基）含量为38.99%，粗脂肪（干基）含量为21.14%。同时介绍了该品种的栽培技术和适宜的栽培区域。     

Production of new soy-based polyols by enzyme hydrolysis of bodied soybean oil

Polyols are one of the predominate reactants in polyurethane synthesis. Soy-based polyols are potentially low-cost materials in plastic and polymer industrials for decades. However, the performance of most commercial soy-based polyols is limited by their low molecular weights (low hydroxy equivalent weights), low alcohol reactivity due to the prominence of secondary moieties, and limited control on crystalline behavior due to large non-functional branches on the soy-based polyols.The objective of this investigation was to produce new soy-based polyols from enzyme hydrolysis. Soy-based polyols were synthesized by a two-step process consisting of heat bodying soybean oil followed by enzyme hydrolysis of bodied soybean oil. Possible advantages of this approach include the production of primary alcohol moieties, reduction of saturated fatty acid moieties, control of hydroxy equivalent weights, and elimination of organic co-reagents.Several commercial enzymes were investigated for removing saturated fatty acids and imparting the hydroxy functional groups in order to produce the better soy-based polyols. The lipase from Candida rugosa significantly hydrolyzed palmitic acid and was recommended to be used to produce the soy-based polyols. Burkholderia cepacia, Aspergillus niger, Mucor javanicus, and Rhizomucor miehei lipases showed some significance in the hydrolysis against palmitic acid and against stearic acid for some reaction conditions.The soy-based polyols were produced with a hydroxy number of about 50 mg KOH/g after only 3 h of the simple hydrolysis reaction by lipase C. rugosa. Higher hydroxy numbers could be obtained with the longer reaction time. However, polyol yield was reduced and undesirable acid residue was increased when the percent hydrolysis increased.     

Wettability and roughness characteristics of modified wood boards using a hot-press

The aim of this study was to investigate the effect of the thermal modification process by hot-press on the wettability and surface roughness characteristics of the eucalyptus wood boards. The roughness measurements, average roughness (R_a), and maximum roughness (R_max) were taken both parallel and perpendicular to the grain using a fine stylus tracing technique. Contact angle measurements were obtained using a goniometer system connected to a digital camera and computer system. The results showed that surface roughness values of the modified wood boards using a hot-press significantly decreased with increasing press pressure and with decreasing temperature. The contact angle measurements indicated that the thermal modification had a significant influence on the surface wettability of the wood boards. Statistical analyses showed significant differences in the surface roughness and contact angle values of the wood boards following thermal modification. The results acquired in this work provide important information for future research and utilization of the thermally modified wood boards.     

Cornstarch and tannin in phenol–formaldehyde resins for plywood production

The aim of this work is to demonstrate the performances of cornstarch–quebracho tannin-based resins designed as adhesive in the plywood production. In this way, the cornstarch and quebracho tannin was introduced in the classic adhesive formulation in order to supply a part of phenol–formaldehyde (PF). The physical properties (rheological characterization, thermogravimetric analysis and solid phase ¹³C NMR analysis) of the formulated resins were measured. In order to evaluate the mechanical performances of optimal cornstarch–quebracho tannin-based resins, plywood panels were produced and mechanical properties were investigated. These mechanical properties included tensile strength, wood failure and 3-point bending strength. The performance of these panels is comparable to those of plywood panels commercial PF made.The results showed that plywood panels bonded with cornstarch–quebracho tannin–PF resins (15:5:80, w/w/w) exhibited better mechanical properties than plywood panels commercial PF made. The introduction of small proportions of cornstarch and quebracho tannin in PF resins contributes to the improvement of the boiling water performance of these adhesives. The formaldehyde emission levels obtained from panels bonded with cornstarch–quebracho tannin–PF were lower to those obtained from panels bonded with control PF. Solid state CPMAS NMR spectra indicates that no reaction at all between PF resins and cornstarch and quebracho tannin. Even when reaction does evidently not occur, the addition of cornstarch and quebracho tannin improves markedly the water resistance of PF resins.     

大豆蛋白在非食品用途中的应用与研究现状

本文综述了大豆蛋白在非食品用途中的应用与研究概况,包括在胶黏剂、织物纤维、可食性包装膜和塑料中的应用,以及为了达到各种应用要求进行的大豆蛋白改性研究。     

Influence of tryptophan supplementation of soy-based infant formulas on protein quality and on blood and brain tryptophan and brain serotonin in the rat model

A 2-wk feeding study with weanling rats was conducted to investigate theeffects of tryptophan supplementation of soy-based infant formulas on proteinquality and on the levels of blood and brain tryptophan and brain serotoninand 5-HIAA (5-hydroxyindole-3-acetic acid), a metabolite of serotonin. Thepowder and liquid concentrate forms of soy-based infant formulas obtainedfrom four manufacturers were tested. The tryptophan contents of the testsoy-based formulas (10.0–12.3 mg/g protein) were considerably lower comparedto those of human milk (17–19 mg/g protein). The infant formulas were fedas the sole source of protein in diets containing 8% protein, 20% fat, 5%cellulose and adequate amounts of minerals and vitamins. In general, supplementation of the diets containing test formulas with graded levels ofL-tryptophan (0.1 or 0.2%) had no effect on protein quality indices basedon rat growth such as PER (protein efficiency ratio), NPR (net protein ratio)and relative NPR (RNPR), but resulted in significant (p<;0.05) increases inthe concentrations of tryptophan in the plasma and brain, and serotonin and5-HIAA in brain of rats. The increased concentrations of brain tryptophan and5-hydroxyindoles (serotonin + 5-HIAA) in rats fed tryptophan-supplementedformulas compared to those fed unsupplemented formulas support the need forfurther research to investigate the influence of tryptophan supplementationof soy-based infant formulas on tryptophan metabolites and their potentialrelated effects on sleep latency and neurobehavioral developments in infants.     

Lignin modification improves the biofuel production potential in transgenic Populus tomentosa

Lignin has been recognized for its negative impact on forage digestibility, tree pulping properties, and cellulosic biofuel production, although it is the major structural component of the secondarily thickened cell walls of vascular plants. Earlier studies have demonstrated that lignin modification improves forage digestibility and poplar pulping properties. To determine whether lignin modification has beneficial effect on saccharification of lignocellulosic biomass, we pretreated and then enzymatically hydrolyzed the mature wood from transgenic poplar plants that expressed the antisense transgenes of monolignol biosynthesis genes 4-coumarate: CoA ligase (4CL) or caffeoyl CoA 3-O-methyltransferase (CCoAOMT). Firstly, a long-term field trial was set up for the transgenic plants. Over five years, the reduced trend of lignin content remained stable in all transgenic lines. And a total lignin reduction of up to 10% did not alter the growth rate or biomass yield of the transgenic poplars. In the mature wood, suppression of CCoAOMT increased saccharification potential, but 4CL down-regulation had no significantly positive effect on saccharification. Sugar yield were negatively correlated with soluble lignin content of dried, extractive-free stem biomass. These results imply that lignin modification can facilitate the process of saccharification for biofuel production in tree crops.     

棉纤维的功能性技术研究进展

棉纤维是一种天然纤维素类大宗纤维,其性能优异及衍生物结构复杂,在棉织物等方面有着广泛应用;也是化学工业的重要原料。作者通过查阅文献资料,针对棉纤维的溶解、物理改性、化学改性方面的研究进展进行了综述,并分析了棉纤维功能性的改性技术发展趋势。同时,基于现有研究,梳理了今后研究者需要去解决的关键问题,为研究棉纤维功能性的改性技术提供参考。