淀粉基木材胶黏剂研究现状与展望

利用廉价的淀粉开发高性能的木材胶黏剂是人类永久的梦.但是传统的淀粉胶黏剂不能用于木材的黏结.早期的淀粉基木材胶黏剂研究是将淀粉在强烈的反应条件下转化为低分子物质来充当酚醛胶的填料.而目前的发展趋势是既要考虑充分利用淀粉的大分子特性,避免过度降解,又要能够向淀粉链中引入足够的均匀分布的化学键,使其与氢键的弱化学作用力有效配合,达到木材胶黏剂耐水的要求.双醛淀粉树脂胶;淀粉、聚乙烯醇和六甲氧甲基三聚氰胺共混胶;淀粉氧化降解接枝改性聚氨酯型胶等都是这类努力的代表性工作.我们的研究结果表明,淀粉经常压快速液化可以制备高活性的多羟基化合物.利用淀粉基多羟基化合物与多元酸（酐）聚合成功地制备了新型聚酯型的木材胶黏剂,成本与酚醛树脂相当,但其施胶量仅为酚醛树脂的1/3～1/2,可以用于高耐水性胶合板的生产.     

淀粉基木材胶黏剂的制备与性能

以玉米淀粉为接枝骨架,过硫酸铵为引发剂,与接枝单体乙酸乙烯酯-丙烯酸丁酯进行接枝共聚反应,制取淀粉基木材胶黏剂。对得到的淀粉接枝共聚物进行了表征分析及性能研究。IR谱图表明,样品除了保持淀粉的特征吸收峰外,在1730—1740cm。之间出现了羰基特征吸收峰。X-粉末衍射图表明,样品多为弥散峰,证明淀粉接枝共聚物基本为少量结晶态与无定形态共存的结构。TG、DTA曲线证实了接枝共聚反应的发生,且淀粉接枝共聚物的热稳定性优于纯玉米淀粉。性能测试结果表明,制备的胶黏剂具有较好的高温稳定性、粘接性,各项指标已达到了国家标准HG／T2727—95中聚乙酸乙烯酯木材胶黏剂的性能指标,特别是压缩剪切干强度远远超过了国家标准。     

改性淀粉木材胶粘剂的制备及表征

以过硫酸铵为引发剂,以玉米淀粉、乙酸乙烯酯和丙烯酸丁酯为原料,制备改性淀粉木材胶粘剂,在单因素实验的基础上,进行L_(16)(4~5)正交实验,优化改性淀粉木材胶黏剂的制备条件。结果表明,最佳制备工艺参数为:引发剂浓度11 mmol/L,单体与淀粉质量比为1.0,反应温度70℃,单体乙酸乙烯酯和丙烯酸丁酯的质量比为3∶2,反应时间3 h。在此条件下,接枝率达91.3%,制备的改性淀粉木材胶粘剂性质较佳,各项指标均达到聚乙酸乙烯酯木材胶粘剂化工行业标准HG/T 2727—2010。     

绿色环保木材用胶黏剂的研究

以过硫酸铵为引发剂制备聚丙烯酰胺预聚体,以次氯酸钠为氧化剂对淀粉进行氧化处理,将两者经过缩合反应得到接枝淀粉胶黏剂的主剂,用氮丙啶进行交联,得到了木材用改性淀粉胶。当缩合温度为60℃、氧化剂量为35mL、丙烯酰胺为淀粉质量的7．5％、交联剂为3％和交联时间3h时制得的胶黏剂胶合强度达到5．30MPa,耐水时间达33h。对各阶段试样进行了红外光谱和x射线衍射分析。     

淀粉胶黏剂的最新研究进展

淀粉胶黏剂作为环境友好型天然胶黏剂越来越受到研究人员的广泛关注,淀粉以其资源丰富、价格低廉、使用方便等优点并以无毒环保为亮点,成为最具有开发潜力的木材用天然胶黏剂之一。综述了淀粉胶黏剂用于木材粘接的最新动态,详述了它在应用中存在的局限性和研究现状,并对淀粉胶黏剂的发展趋势进行了展望。同时还指出在提高淀粉胶黏剂的耐水性、贮存稳定性、防潮防霉性能方面仍有很大的发展空间,因而广大学者致力于淀粉胶黏剂的进一步开发研究。     

MF改性的淀粉胶黏剂的合成与性能研究

对玉米淀粉进行氧化、聚合处理,再使用MF改性,制得防水高黏型淀粉胶粘剂。同时采用正交实验法查验了淀粉糊化温度、NaClO相对于淀粉的质量比、PVA溶液质量分数和MF相对于淀粉的质量比对胶黏剂性能的影响。得到一款防水高黏型淀粉胶黏剂的制备条件为:PVA质量分数20%,淀粉糊化温度55℃,MF投料比1.25,NaClO投料比1%。在此条件下胶黏剂粘度达到GB/T 2794-1995的标准,耐水性能符合QB/T l094—1991的标准。     

改性淀粉木材胶粘剂的制备及性能研究

以玉米淀粉为接枝骨架、聚乙烯醇(PVA)为保护胶体、过硫酸铵(APS)为引发剂、乙酸乙烯酯(VAc)和丙烯酸丁酯(BA)为接枝单体,采用接枝共聚法制备了改性淀粉木材胶粘剂。研究结果表明:当w(淀粉)=20%(相对于胶粘剂质量而言)、m(BA)∶m(VAc)=3∶1、m(引发剂)=0.32 g、V(氧化剂)=0.8 m L和m(PVA)=3.5 g时,改性淀粉木材胶粘剂的综合性能相对较好,其各项性能均达到HG/T 2727—2010标准中的指标要求。     

葛根淀粉基胶黏剂制备与性能研究

研究开发以淀粉为主要原料的环保型胶黏剂替代"三醛类"木材胶黏剂,对彻底解决人造板及其制品的甲醛释放问题具有重要意义。以野生葛根淀粉为原料,通过降黏处理,并与聚醋酸乙烯酯和异氰酸酯复配,制备出胶合强度达到国家Ⅱ类要求的淀粉基木材胶黏剂。研究了降黏剂用量、降黏时间、聚醋酸乙烯酯和异氰酸酯用量对淀粉基木材胶黏剂胶合强度的影响。优化工艺条件下制备胶黏剂胶接胶合板的胶合强度为1.89 MPa,能够满足国家Ⅱ类胶合板强度要求。     

接触快速固化型水基木材胶黏剂的研究

用PVOH为保护胶,通过乳液聚合制得了带有活性反应基团的聚醋酸乙烯酯乳液,并以此为甲组分,以含有酰肼基团的高分子聚合物为乙组分,制成了可快速固化的接触固化型木材胶黏剂,实现了木材的快速粘接。并对PVOH及酰肼基团的含量对胶黏剂性能的影响进行了研究。结果表明：所制胶黏剂的最佳配比为甲组分中PVOH含量为4．5％,乙组分中酰肼基团浓度为0．8mol／L。     

木材用大豆蛋白基胶黏剂专利申请分析

大豆蛋白基胶黏剂是一种绿色环保型胶黏剂,在木材工业中具有广泛地应用。本文对世界范围内的大豆蛋白基胶黏剂技术专利文献进行收集整理,从大豆蛋白基胶黏剂的全球专利申请量趋势、主要申请人、专利产出国和目标国申请量等多维角度,对大豆蛋白基胶黏剂进行宏观总体分析。     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。