酯交换合成聚醚型聚氨酯的工艺探究

以聚四氢呋喃二醇、1,6-六亚甲基二氨基甲酸甲酯、1,4-丁二醇为原料,通过酯交换缩聚合法制备了聚醚型聚氨酯。确定工艺条件为:预缩聚合压力0.07 MPa,预缩聚合温度110℃,预缩聚合时间45 min;真空条件下缩聚合,缩聚合温度190℃,缩聚合时间110 min。根据各因素影响效应的主次关系,可控制产物特性黏度为75.17~128.56 cm~3/g,实现相对分子质量为(7.5~12.5)×10~4,可根据相对分子质量需求合成产物。将得到的聚醚型聚氨酯弹性体在170℃下熟化时间4 h后,产物特性黏度为126.78 cm3/g,拉伸强度为17.46 MPa,拉断伸长率为2 348%。     

钛酸四乙酯催化酯交换缩聚法合成聚醚型聚氨酯

以钛酸四乙酯(TET)为催化剂,聚四氢呋喃醚二醇(PTMG)和1,6-六亚甲基二氨基甲酸甲酯(HDC)为原料,1,4-丁二醇为扩链剂,酯交换缩聚合成了聚醚型聚氨酯(PEPU)弹性体。以二丁基氧化锡(DBTO)催化合成的PEPU为参考,通过红外光谱(FTIR)、凝胶色谱(GPC)、热重分析(TGA)、力学性能与光学性能测试表征TET的催化效果。通过一系列单因素实验探讨了缩聚温度、缩聚时间、预聚温度、预聚时间对PEPU特性黏度的影响规律。结果表明,TET比DBTO催化制得的PEPU热性能更好,力学性能更优。较佳的制备工艺为:预聚阶段温度为110℃,压力为0.070MPa,时间为20min;160℃下高真空缩聚110min.     

异山梨醇型聚碳酸酯的合成工艺研究

以异山梨醇(IS)和碳酸二苯酯(DPC)为主要原料,利用熔融酯交换法合成了异山梨醇型聚碳酸酯(PIC)。考察了原料摩尔比、缩聚温度、预聚温度、预聚压力、催化剂种类及用量对PIC特性黏度的影响,并对其外观、结构、热性能和分子质量进行了测试。较优的合成工艺条件为:乙酰丙酮锂为催化剂,用量为13.5×10-4mol/(mol IS),DPC和IS的摩尔比为1∶1,缩聚温度为210℃,预聚温度为110℃,预聚压力为0.04 MPa。在该条件下所得PIC的特性黏度为46.72 m L/g,数均分子质量为1.98×104,色差为3.89,玻璃化转变温度(Tg)为144℃。     

蓖麻油基聚醚型聚氨酯弹性体的制备与工艺研究

以蓖麻油基聚氧乙烯醚(EL)和聚四氢呋喃醚二醇(PTMG)为软段,1,6-六亚甲基二氨基甲酸甲酯(HDC)为硬段,二月桂酸二丁基锡(DBTDL)为催化剂,1,4-丁二醇(1,4-BDO)为扩链剂,采用酯交换缩聚法制备蓖麻油基聚醚型聚氨酯弹性体(CEUs)。利用红外光谱、热重分析、拉伸性能测试等对CEUs进行分析与表征。通过单因素对比实验探讨了物料配比、预聚阶段的温度、时间和压力及缩聚阶段的温度和时间等对蓖麻油基聚醚型聚氨酯弹性体力学性能的影响。结果表明,较优的制备工艺条件为:n(EL)∶n(PTMG)=1∶5、n(软段)∶n(硬段)=1∶1. 07、预聚温度为110℃、预聚时间为45 min、预聚压力为0. 03 MPa、缩聚温度为170℃、缩聚时间为180 min。在该制备工艺条件下,伸长率达到972. 38%,断裂拉伸强度为3. 23 MPa,邵尔A硬度为60。     

紫外光固化丙烯酸酯化聚硅氧烷的合成及其弹性体性能研究

以二甲基二乙氧基硅烷(DMDESi)和γ-甲基丙烯酰氧基丙基甲基二甲氧基硅烷(USi-3311)为原料,四甲基氢氧化铵(TMAH)为催化剂,通过水解-缩聚反应合成了一种可快速紫外光固化成型为弹性体的丙烯酸酯化聚硅氧烷,并对缩聚反应条件、紫外光固化动力学及其弹性体性能进行了研究。结果表明,水解温度为60℃,水解时间为2 h,催化剂质量分数为0. 7%,缩聚温度为95℃,缩聚时间为1. 5 h,DMDESi和USi-3311的量之比为50∶1时,合成的丙烯酸酯化聚硅氧烷的黏度为2 528 m Pa·s,双键含量为12 mmol/100 g;光固化过程中双键转化率为90%,凝胶时间为4. 5 s;光固化弹性体的玻璃化温度为-126℃,拉伸强度和拉断伸长率分别为70 k Pa和107%。     

固相缩聚合成高分子量双酚A型聚碳酸酯

研究了以碳酸二苯酯和双酚A为原料,有机胺为催化剂,固相缩聚法合成高分子量双酚A型聚碳酸酯(BPA–PC)的新工艺。探究了预聚体粉料颗粒大小、缩聚温度、缩聚时间、预聚体分子量及官能团比例等工艺条件对产品性能的影响。结果表明,以四乙基氢氧化铵为催化剂,大于60目(小于250μm)的预聚体颗粒在210℃真空缩聚8 h,制得的缩聚体特性黏度较大。预聚体分子量越大,C6H5OH/OH官能团比例越接近1,缩聚物的分子量越大。在较佳工艺条件下,可得到数均分子量为52 572、分子量分布为1.830、熔点258℃、有一定结晶度的BPA–PC产品。     

PEG/PTMG共聚醚型聚氨酯弹性体制备工艺的研究

以聚乙二醇(PEG)和聚四氢呋喃醚二醇(PTMG)为软段、1,6-六亚甲基二氨基甲酸甲酯(HDC)为硬段、二月桂酸二丁基锡(DBTDL)为催化剂、1,4丁二醇为扩链剂,采用酯交换缩聚法制备共聚醚型聚氨酯弹性体(CEUs)。通过一系列单因素对比实验,探讨了物料配比、预聚温度、预聚时间、缩聚温度和缩聚时间等对聚氨酯弹性体力学性能的影响。结果表明,在物料配比n(PTMG+PEG)∶n(HDC)∶n(BDO)=1.0∶0.9∶0.1、预聚温度为130℃、预聚时间为45 min、缩聚温度为175℃、缩聚时间为180 min的条件下,聚氨酯弹性体的断裂拉伸强度为61 MPa,断裂拉伸率为2718%。     

钛硅分子筛催化制备聚丁二酸丁二醇酯的研究

本文以丁二酸、丁二酸酐和1,4-丁二醇为原料,以自制的微孔钛硅分子筛为聚合催化剂,制备了高相对分子质量的聚丁二酸丁二醇酯。考察了原料物质的量比、酯化时间、酯化温度对酯化反应的影响,以及缩聚时间、缩聚温度、分子筛种类和用量对聚丁二酸丁二醇酯性能的影响。结果表明,当丁二酸、丁二酸酐和丁二醇的物质的量比为0.5:0.5:1.3,酯化温度为150℃,反应2.5 h酯化率达到95.2%;当以制备的钛硅分子筛为缩聚催化剂,其用量为酯化产物总质量的1%,缩聚温度为220℃,反应3 h,产物聚丁二酸丁二醇酯的特性粘度可以达到2.0 d L/g,相对分子质量可以达到12.9万g/mol以上。     

合成温度对PCL型聚氨酯弹性体性能的影响

以聚己内酯二元醇(PCL-2000)、甲苯二异氰酸酯(TDI)、3,3’-二氯-4,4’-二氨基二苯甲烷(MOCA)为原料,采用预聚体法合成浇注型聚氨酯弹性体(CPU)。研究了预聚体温度,后熟化温度对聚氨酯弹性体力学及耐热性能的影响。实验结果表明:随着预聚体温度升高,CPU拉伸强度增大,压缩永久形变(80℃×24 h)逐渐变小。随着后熟化温度升高,CPU拉伸强度先增大后减小,压缩永久形变(80℃×24 h)先减小后增大。当预聚体温度为110℃时,拉伸强度达到50 MPa,断裂伸长率达到356%。压缩永久形变80℃×24 h为36%。     

可生物降解高相对分子质量聚丁二酸丁二醇酯制备的研究

以丁二酸、丁二酸酐和1,4-丁二醇为原料,以偏钛酸-乙二醇体系为缩聚催化剂,采用酯化-缩聚法制备了高相对分子质量的聚丁二酸丁二醇酯。考察了原料组成、酯化温度、缩聚时间、缩聚温度、催化剂用量等对PBS性能的影响。结果表明,当n(丁二酸+丁二酸酐):n(1,4-丁二醇)=1:1.2,n(丁二酸):n(丁二酸酐)=1:1,酯化温度为130℃,缩聚时间为2.5 h,缩聚温度为230℃,缩聚催化剂(按照偏钛酸计算)用量为n(丁二酸+丁二酸酐)的0.4%时,制备的PBS的特性粘度为2.04 dL/g,相对分子质量为2.35×10~5g/mol。     

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。