瓦楞纸板用淀粉粘合剂制造方法的探讨

介绍了瓦楞纸板用淀粉粘合剂的制备方法,包括过氧化氢、次氯酸钠和高锰酸钾等氧化剂的氧化法;并对淀粉粘合剂质量的影响因素进行了讨论。这将有助于淀粉粘合剂的生产和应用。     

太湖湖滨带生态系统健康评价

根据湖滨带生态系统的特点,运用综合健康指数法建立了湖滨带生态系统健康评价体系,由目标层、准则层、指标层构成,其中准则层由湖滨带水质状况、底泥状况、植被状况、其它生物状况(浮游动物、浮游植物、底栖动物)、岸带物理状况5项组成,指标层由总氮、总磷、溶解氧、挺水植物覆盖率等15项指标构成。采用专家打分法、熵值法分别确定了准则层、指标层的权重系数。对太湖湖滨带33个点位进行了采样分析,并进行无量纲化处理后应用到所建立的评价体系中。评价结果显示33个点位中为"很健康"、"健康"、"亚健康"、"疾病"、"严重疾病"的分别占0%、24.2%、21.2%、51.5%及3.0%,也即超过一半的点位处于"疾病"状态。只有东太湖刚刚超过"健康"分数的下限,东部沿岸、贡湖、南部沿岸均处于"亚健康"状态,而梅梁湾、竺山湾、西部沿岸属于"疾病"状态,且竺山湾的生态健康状态最差。该评价结果与太湖湖滨带各分区的实际调查情况相符合,评价方法可靠性、可行性较强,可为其它湖泊湖滨带的生态系统健康评价提供一定的参照。     

基于聚苹果酸的贻贝仿生粘合剂的制备及性能研究

目的:以实验室制得的聚苹果酸(PMLA)为高分子骨架,通过酰胺化反应将多巴胺(DA)分子连接到聚苹果酸,制得既具有良好粘合性能,又有优异生物相容性的贻贝仿生粘合剂。方法:L-天冬氨酸通过内酯开环聚合法合成高分子化合物聚苹果酸,将PMLA与DA加EDC/NHS反应得到粘合剂PMLA-DA,傅里叶变换红外光谱、核磁氢谱、紫外可见光光谱等对其进行结构表征,标准曲线法测多巴胺取代度,采用搭接剪切测试法评估粘合剂对不锈钢、玻璃、猪皮三种材质的粘合强度,MTT法检测贻贝仿生粘合剂的细胞毒性,通过降解试验验证PMLA-DA的降解性能。结果:测得PMLA-DA中多巴胺的取代度能达到21.3%,搭接剪切试验测得粘合剂对猪皮的粘合强度为22.68 kPa,高于目前市场上常用的生物医用粘合剂纤维蛋白胶15.38 kPa的粘合强度,PMLA-DA对不锈钢与玻璃亦有很好的粘合性能。细胞毒性研究和体外降解试验显示PMLA-DA无细胞毒性,降解性能良好。结论:通过聚苹果酸与多巴胺反应制得贻贝仿生粘合剂PMLA-DA,该粘合剂对多种材质均具有良好的粘合力;无细胞毒性,降解性能良好,对皮肤组织的粘合强度优于目前商用的生物粘合剂纤维蛋白胶。无论是对无机材料间的粘接,或者是医学领域的伤口粘合,均具有良好的应用前景。     

急诊医疗中医用粘合剂的研究进展

医用粘合剂是能够应用于医疗范畴的一类具有一定生物相容性和高度粘合力的医学材料;并已得到广泛的关注和研究。本文对当前急诊医疗中医用粘合剂的分类、各类粘合剂的作用机理、特点及应用范畴、医用粘合剂复合生物材料构成复合物的基础和应用研究现状等做一回顾及评价,并对未来医用粘合剂的研究和发展趋势进行了展望。     

三江源自然保护区森林-草甸交错带植物优先保护序列研究

运用系统分析方法和原理,在资料收集和实地调查的基础上,借助专家咨询系统构建了三江源自然保护区森林一草甸交错带植物受威胁等级、优先保护定量分级评价指标体系以及相应的定量评价标准．评价体系包括物种濒危系数、遗传损失系数和利用价值系数3个评价系统层和10个评价指标层．利用专家咨询法和层次分析法,定量确定各个系统层和指标层的权重．通过数学模型和计算机程序计算,分别度量了三江源自然保护区森林．草甸交错带植物物种受威胁状况和优先保护序列状况的濒危系数和优先保护系数;对照植物濒危等级和优先保护序列区域性评价标准,定量评价了植物物种濒危等级和优先保护等级．评价结果表明,三江源自然保护区森林．草甸交错带的种子植物有濒危种4种,脆弱种68种,敏感种179种,安全种695种;该地区种子植物一级保护物种8种,二级保护物种78种,三级保护物种164种。暂缓保护物种696种．最后,针对植物物种优先保护序列评价的指标体系与权重分配问题。物种濒危等级与优先保护序列之间的关系,物种濒危等级评价的空间尺度问题进行了分析和探讨。     

基于异肽键连接的分子粘合剂研究进展

异肽键分子粘合剂是多肽链中的赖氨酸(Lys)残基和天冬酰胺或天冬氨酸(Asn/Asp)残基侧链自发结合形成的不可逆共价键,具有良好的特异性和稳定性。该反应可在极短的时间完成,且不需要特定的理化环境和催化剂。文中结合近年来国内外学者对异肽键分子粘合剂的研究进展,综述了异肽键分子粘合剂的来源、类型、形成机制及其介导的分子环化和蛋白拓扑结构,并讨论了其在合成疫苗、水凝胶和细菌纳米生物反应器等领域的应用前景。     

BP人工神经网络紫外分光光度法同时测定三种氨基酸

应用人工BP神经网络紫外分光光度法,不经分离,同时测定了色氮酸、酪氮酸和苯丙氮酸,采用均匀实验设计法,确定了最佳网络运行参数;比较了三层和四层BP神经网络的预测能力;用预测能力较好的三层BP神经网络同时测定了复方氮基酸注射液中色氮酸、酪氮酸和苯丙氮酸,相对平均误差分别为1．09％、3．71％和2．40％。     

水、甲醇、乙醇对含水脑磷脂液晶结构影响的X射线衍射研究

用小角X射线散射法(SAXS)对含水脑磷脂分别用水、甲醇和乙醇实验所形成的液晶体系结构进行了研究。实验结果证明:在脑磷脂-水体系中,随着水含量增加,脑磷脂和水形成的双分子层液晶体系的层间距变大;在脑磷脂-甲醇体系中,随着甲醇含量增加,它们的层间距变小。在脑磷脂-乙醇体系中,随着乙醇含量的增加,它们的层间距先由小到大,继而又由大变小,然后液晶相逐渐消失,最后变成液态。水和甲醇、乙醇相比,水有使层间距变大的趋势,醇类有使层间距变小的趋势,随着醇中碳链的增长,层间距减小的趋势增大。     

光滑漆树的成分及其应用

用植物材料充当类脂物燃料可以减轻人类对矿物燃料的依赖,其中,光滑漆树是很有前途的一种。光滑漆树是多年生木本植物,含多酚和油,全株皆可利用。它的多酚由酚醛、红粉、单宁和一些复杂的类脂化合物组成。其多酚物的用途很广,诸如木层树脂、胶合板胶、粘合剂、淀粉粘合剂中的强化剂、油井固沙剂、塑料配方以及抗氧化剂等。另外,单宁是皮     

微生物法生产对苯二甲酸进展

对苯二甲酸(terephthalic acid,TPA)是一种重要的有机工业化学品,广泛应用于聚酯、纤维、涂料、粘合剂和薄膜等行业的生产,目前主要采用对二甲苯的化学氧化法进行生产。本文综述了微生物法生产TPA的方法和国内外的生产现状以及研究进展。     

Environment-friendly adhesives for surface bonding of wood-based flooring using natural tannin to reduce formaldehyde and TVOC emission

The objective of this research was to develop environment-friendly adhesives for face fancy veneer bonding of engineered flooring using the natural tannin form bark in the wood. The natural wattle tannin adhesive were used to replace UF resin in the formaldehyde-based resin system in order to reduce formaldehyde and volatile organic compound (VOC) emissions from the adhesives used between plywoods and fancy veneers. PVAc was added to the natural tannin adhesive to increase viscosity of tannin adhesive for surface bonding. For tannin/PVAc hybrid adhesives, 5%, 10%, 20% and 30% of PVAc to the natural tannin adhesives were added. tannin/PVAc hybrid adhesives showed better bonding than the commercial natural tannin adhesive with a higher level of wood penetration. The initial adhesion strength was sufficient to be maintained within the optimum initial tack range. The standard formaldehyde emission test (desiccator method), field and laboratory emission cell (FLEC) and VOC analyzer were used to determine the formaldehyde and VOC emissions from engineered flooring bonded with commercial the natural tannin adhesive and tannin/PVAc hybrid adhesives. By desiccator method and FLEC, the formaldehyde emission level of each adhesive showed the similar tendency. All adhesives satisfied the E(1) grade (below 1.5 mg/L) and E(0) grade (below 0.5 mg/L) with UV coating. VOC emission results by FLEC and VOC analyzer were different with the formaldehyde emission results. TVOC emission was slightly increased as adding PVAc.     

白蚁纤维素粉饵料成型技术研究

为研究白蚁饵料成型工艺,比较了9种胶黏剂对白蚁纤维素饵料成型效果、耐水性能以及对白蚁取食的影响。结果表明:20%、40%剂量糊精;50%、100%剂量三聚氰胺甲醛树脂,10%、20%、40%田菁胶、卡拉胶、壳聚糖、明胶;10%、50%、100%聚乙烯醇、硅酸钠对微晶纤维素的成型效果较好,经上述剂量胶黏剂处理后,纤维素饵块的邵氏硬度(HD)极显著高于对照。耐水性能试验至第30天时,50%聚乙烯醇、100%聚乙烯醇、100%三聚氰胺甲醛树脂处理的纤维素饵块的溃散程度指数分别为1.33、1.00、2.00,其余饵块的溃散程度指数均达3级。生测结果显示,在7 d的室内强迫取食试验中,白蚁对50%聚乙烯醇、100%聚乙烯醇、100%三聚氰胺甲醛树脂处理的块状纤维素饵料的取食率均极显著低于对照,说明饵块中添加的上述胶黏剂对白蚁的取食具有一定的影响。综上,50%聚乙烯醇、100%聚乙烯醇、100%三聚氰胺甲醛树脂适用于白蚁纤维素饵料成型,但若想获得白蚁喜食的饵块仍需对配方做进一步的优化。     

Comparison of tensile bond strengths of four one-bottle self-etching adhesive systems with Er:YAG laser-irradiated dentin

This study aimed to investigate the interaction of current one-bottle self-etching adhesives and Er:YAG laser with dentin using a tensile bond strength (TBS) test and scanning electron microscopy (SEM) in vitro. Two hundred and thirteen dentin discs were randomly distributed to the Control Group using bur cutting and to the Laser Group using an Er:YAG laser (200 mJ, VSP, 20 Hz). The following adhesives were investigated: one two-step total-etch adhesive [Prime & Bond NT (Dentsply)] and four one-step self-etch adhesives [G-Bond plus (GC), XENO V (Dentsply), iBond Self Etch (Heraeus) and Adper Easy One (3 M ESPE)]. Samples were restored with composite resin, and after 24-hour storage in distilled water, subjected to the TBS test. For morphological analysis, 12 dentin specimens were prepared for SEM. No significant differences were found between the control group and laser group (p = 0.899); dentin subjected to Prime & Bond NT, XENOV and Adper Easy One produced higher TBS. In conclusion, this study indicates that Er:YAG laser-prepared dentin can perform as well as bur on TBS, and some of the one-step one-bottle adhesives are comparable to the total-etch adhesives in TBS on dentin.     

Marine adhesive proteins: natural composite thermosets

Marine environments are severely challenging for the performance and durability of synthetic adhesives. Factors commonly associated with adhesive failure are weak boundary layers (water, oxides), adhesive erosion and swelling. For many permanently attached marine organisms such as barnacles, mussels, oysters, etc., however, underwater adhesion is 'business-as-usual'. Knowledge about the chemistry and bioprocessing of these marine adhesives will provide profound insights for the evolution of a new generation of environmentally safe, water-resistant adhesives. Despite their apparent structural diversity, marine adhesives are essentially analogous to composite thermosets, that is, the adhesive consists of fibre, filler and catalyst molecules that are dispersed in a cross-linked resin rendering it resistant to heat and solvents. The fibres and fillers in these composites are variable. e.g. collagen, fibroin, chitin present as fibres, and sand, shell, air and water present as fillers. The precured resins of seven organisms including members of the Mollusca, Annelida, and Platyhelminthes have now been isolated and partially sequenced. These are proteins with basic isoelectric points, high levels of the amino acid 3,4-dihydroxyphenyl-L-alanine (DOPA), and an extended, flexible conformation. The DOPA functional group in particular is thought to play a key role in (a) the chemisorption of these polymers to surface underwater, and (b) covalent cross-linking or setting of the adhesive, the latter reaction catalysed by the enzyme catecholoxidase. Much more needs to be done to explore the details of the adhesive processing and delivery strategies used by these organisms.     

纸浆废液中有机物资源的利用

将硫酸盐纸浆废液浓缩后,100%用作生产木材胶粘剂的原料.对废液中木素进行活化处理,用酚醛树脂、PAPI增强废液胶的效果.结果表明,在废液中加入甲醛后,可提高废液中木素的反应活性;用30%甲阶酚醛树脂或20%PAPI作增强剂,可使废液混合胶代替纯酚醛树脂生产Ⅰ类胶合板;原料成本比纯酚醛树脂分别降低了55.5%和49.0%.该法充分利用了废液中的有机物资源,减少了环境污染,具有较好的经济、社会和生态效益.文中还运用红外光谱分析了废液制胶粘剂方法的可行性.     

An Experimental Study of Hafting Adhesives and the Implications for Compound Tool Technology

Experimental studies of hafting adhesives and modifications to compound tool components can demonstrate the extent to which human ancestors understood and exploited material properties only formally defined by science within the last century. Discoveries of Stone Age hafting adhesives at archaeological sites in Europe, the Middle East, and Africa have spurred experiments that sought to replicate or create models of such adhesives. Most of these studies, however, have been actualistic in design, focusing on replicating ancient applications of adhesive technology. In contrast, this study tested several glues based on Acacia resin within a materials science framework to better understand the effect of each adhesive ingredient on compound tool durability. Using an overlap joint as a model for a compound tool, adhesives formulated with loading agents from a range of particle sizes and mineral compositions were tested for toughness on smooth and rough substrates. Our results indicated that overlap joint toughness is significantly increased by using a roughened joint surface. Contrary to some previous studies, there was no evidence that particle size diversity in a loading agent improved adhesive effectiveness. Generally, glues containing quartz or ochre loading agents in the silt and clay-sized particle class yielded the toughest overlap joints, with the effect of particle size found to be more significant for rough rather than smooth substrate joints. Additionally, no particular ochre mineral or mineral mixture was found to be a clearly superior loading agent. These two points taken together suggest that Paleolithic use of ochre-loaded adhesives and the criteria used to select ochres for this purpose may have been mediated by visual and symbolic considerations rather than purely functional concerns.     

Interactions of polysaccharide-based tissue adhesives with clinically relevant fibroblast and macrophage cell lines

The effects of polysaccharide-based tissue adhesives on cell survival and inflammatory cell activation were determined using in vitro mouse cell cultures. Cytotoxicity of tissue adhesives was evaluated by placing adhesives in direct contact with 3T3 fibroblast cells. Polysaccharide-based tissue adhesives composed of dextran aldehyde and star PEG amine were non-cytotoxic to fibroblasts; in contrast, a commercial adhesive composed of 2-octyl cyanoacrylate was highly cytotoxic to fibroblasts. The inflammatory potential of tissue adhesives was evaluated by exposing J774 macrophage cells to adhesives, and measuring TNF-α release from macrophages. Polysaccharide-based tissue adhesives did not elicit inflammatory TNF-α release from macrophages. These results suggest that polysaccharide-based tissue adhesives are non-cytotoxic and non-inflammatory; the results are therefore significant in the design of in vitro cell culture systems to study biomaterials.     

Poly(vinyl alcohol) acetoacetate-based tissue adhesives are non-cytotoxic and non-inflammatory

Polymer-based tissue adhesives composed of poly(vinyl alcohol) acetoacetate (PVOH acac) and cross-linking amines were investigated for their effects on cell survival and inflammatory cell activation using in vitro mouse cell cultures. Cytotoxicity of tissue adhesives was evaluated by placing adhesives in direct contact with 3T3 fibroblast cells. Tissue adhesives formulated from PVOH acac and 3-aminopropyltrialkoxysilane (APS) were non-cytotoxic to fibroblasts; adhesives formulated from PVOH acac and aminated poly(vinyl alcohol) (PVOH amine) were also non-cytotoxic to fibroblasts. In contrast, a commercial adhesive composed of 2-octyl cyanoacrylate was highly cytotoxic to fibroblasts. The inflammatory potential of tissue adhesives was evaluated by exposing J774 macrophage cells to adhesives, and measuring TNF-α release from macrophages. PVOH acac-based tissue adhesives did not elicit inflammatory TNF-α release from macrophages. These results suggest that PVOH acac-based tissue adhesives are non-cytotoxic and non-inflammatory. Such tissue adhesives represent a promising technology for a variety of medical applications, including surgical wound closure and tissue engineering, and the results are also significant in the design of in vitro cell culture systems to study biomaterials.     

Mutagenic action of methyl 2-cyanoacrylate vapor

Alkyl 2-cyanoacrylate adhesives were tested for mutagenicity in Salmonella typhimurium strains TA98, TA100, TA1535 and TA1538. Both a normal spot test and a spot test specially designed to test volatile compounds were used. The adhesives were also tested in the plate incorporation assay. These investigations showed that methyl 2-cyanoacrylate adhesives are mutagenic in strain TA100. The spot test for volatile compounds showed that it is the vapors from the methyl 2-cyanoacrylate monomer that are responsible for the mutagenic effect. One can conclude that working with methyl 2-cyanoacrylate adhesives entails exposure to vapors with a mutagenic effect and may therefore pose a carcinogenic hazard. Because the adhesives are used in industry, their mutagenic effect has a special importance in work environment.     

Irritation and cytotoxic potential of denture adhesives

Objective: The present study aimed to examine the in vitro biocompatibility of denture adhesives. Background: Denture adhesives absorb water to become viscous and sticky, and by this process, other constituents like colouring, flavouring, wetting and preserving agents may be released. Some of these constituents may induce adverse reactions among users of denture adhesives. Materials and methods: Five commercially available denture adhesives; three different creams, a powder, and a cushion were included in the study. The irritation and cytotoxic potential was evaluated using the Hen's Egg Test Chorioallantoic Membrane (HET‐CAM) method and three cell culture methods; filter diffusion, dimethylthiazol diphenyltetrazolium bromide (MTT) assay and agar diffusion. Results: None of the tested denture adhesives showed a noteworthy acute irritation as evaluated by the HET‐CAM method. None of the tested denture adhesives induced cytotoxicity in the filter diffusion test. One of the denture adhesives induced a severe cytotoxic reaction in both the MTT and agar diffusion assays. These tests employ longer exposure times than in both the filter diffusion and the HET‐CAM test. Conclusion: Denture adhesives are commonly used throughout the day, and our results raise the concern that denture adhesives may contribute to mucosal inflammation in denture wearers.