PF泡沫塑料对PF/EPS复合泡沫塑料性能的影响

研究出一种具有较好稳定性、保温性能、力学性能和阻燃性能的酚醛树脂(PF)/可发性聚苯乙烯(EPS)复合泡沫塑料。在PF泡沫塑料颗粒基体中加入EPS发泡颗粒,充分混合固化,使PF泡沫塑料颗粒与EPS发泡颗粒紧密结合,EPS发泡颗粒被PF泡沫塑料颗粒包围并相互隔离,再用模具发泡成型得到该复合泡沫塑料。实验结果表明,PF的含量越高,稳定性、力学性能和阻燃性能越好,保温性能呈现先升高后下降的趋势,当PF的含量为80%时,PF/EPS复合泡沫塑料的表观密度为38.4 kg/m3,热导率为0.024 W/(m·K),弯曲强度为0.134 k Pa,压缩强度为323 k Pa,极限氧指数为47.9%,烟密度等级小于15,热释放速率峰值小于250 k W/m2,综合性能最好。     

玻璃纤维增强尼龙66复合材料的结构与性能

使用双螺杆挤出机,采用共混改性方法制备玻璃纤维(GF)增强尼龙66(PA 66)复合材料(GF-PA 66),并对其结构、热性能和力学性能进行了表征。结果表明:制备的GF质量分数分别为20%,25%,30%的GF-PA 66复合材料的密度均低于1.4 g/cm~3,GF在GF-PA 66复合材料体系中呈现纤维交错复杂的网络结构;GF-PA 66复合材料的起始热降解温度均在320℃以上,具有较好的耐热性;随着GF含量的增加,GF-PA 66复合材料的拉伸强度、弯曲强度、弯曲模量升高,当GF质量分数达到30%时,复合材料的拉伸强度为147.4 MPa,比纯PA 66提高了75%,弯曲强度达到202 MPa,比纯PA 66提高了112%,弯曲模量达到7 783.3 MPa,比纯PA 66提高了175%;随着GF含量的增加,GF-PA 66复合材料的悬臂梁冲击强度先降低后升高,当GF质量分数为30%时,复合材料的悬臂梁冲击强度高于纯PA 66。     

高性能聚氯乙烯复合材料的研究

以聚氯乙烯(PVC)为基体、热塑性聚氨酯弹性体(PUR–T)为增韧剂、连续玻璃纤维(GF)为增强剂,通过熔体浸渍挤出工艺制备高性能PVC复合材料,并对其力学性能、耐热性能和动态力学性能进行研究。结果表明,随着PUR–T或连续GF含量增加,复合材料的力学性能和耐热性能均得到提高,当PUR–T/PVC质量比为2/8,连续GF质量分数为30%时,复合材料的拉伸强度、缺口冲击强度、弯曲强度、弯曲弹性模量、维卡软化温度分别为83.42 MPa,19.81 k J/m2,106.33 MPa,8 823.36 MPa和74.1℃;随着连续GF含量增加,复合材料的储能模量和玻璃化转变温度提高,损耗因子降低;扫描电子显微镜测试结果表明连续GF在PVC中保持了较长的长度,分散性良好。     

三乙醇胺对硬质聚氨酯泡沫塑料性能的影响研究

制备了孔径约0.5 mm的全水发泡硬质聚氨酯泡沫塑料。研究了三乙醇胺(TEA)用量对聚氨酯泡沫塑料发泡时间、表观密度、导热性能、力学性能等的影响规律。TEA是体系反应的催化剂,随着TEA含量增大后发泡时间变短。TEA含量少于7份时,发泡反应强于凝胶反应,制品泡孔直径随着其含量增加而变大,表观密度、热导率、压缩强度、拉伸强度和弯曲强度下降,断裂伸长率上升。TEA含量大于7份时,交联作用占主要地位,制品泡孔直径随着其含量增加而变小,表观密度、热导率、压缩强度、拉伸强度和弯曲强度上升。热失重分析也表明TEA含量大于7份后产生了交联作用。     

玻纤形态对长玻纤增强聚丙烯性能的影响

通过预混粉体浸渍工艺成型方法,制备了玻纤(GF)长度为6,12,24 mm的GF增强聚丙烯复合材料,研究了GF长度和含量对复合材料力学性能、热性能、结晶性能和动态力学性能等的影响,并利用扫描电子显微镜观察其冲击断面形态。结果表明,随着GF含量和长度的增加,复合材料的拉伸强度和冲击强度提高,在GF长度为6,12,24 mm时,复合材料的拉伸强度在GF质量分数为40%时比10%时分别提高160%,200%,200%;随着GF含量和长度的增加,复合材料的热变形温度和结晶性亦有明显的提高;冲击断面形态显示GF的加入起到阻碍裂纹扩展的作用。     

端羟基液体丁腈橡胶对聚氨酯泡沫塑料性能的影响

采用一步法制备聚氨酯硬质泡沫塑料(RPUF)。考察了端羟基液体丁腈橡胶(HTBN)对聚氨酯硬质泡沫塑料表观密度、吸水性能、力学性能等的影响。结果表明:随着HTBN含量的增加,硬泡PU制品的密度逐渐降低,压缩强度、弯曲强度呈降低趋势,吸水率增加。     

甲醛/苯酚配比对酚醛泡沫塑料性能的影响

将甲醛溶液、多聚甲醛共同与苯酚反应,在NaOH碱性催化剂作用下,通过逐步共聚制备可发性甲阶酚醛树脂(PF),然后将可发性甲阶PF与环保型发泡剂、匀泡剂和自制复合酸固化剂混合制备了阻燃绝热PF泡沫塑料.通过对甲醛/苯酚配比(物质的量之比即F/P)进行单因素分析,重点研究了制得的PF泡沫塑料的泡孔结构、力学性能、绝热性能和阻燃性能,并通过锥形量热仪对PF泡沫塑料的燃烧性能进行了分析.结果表明,当F/P=2.0时,制得的PF泡沫塑料泡孔均匀致密,其孔径为268 μm,弯曲强度为0.24 MPa,压缩强度为0.39 MPa,热导率为0.046 W/(m·K),氧指数为54.3%,热释放速率为0.57 kW/m2,烟灰产率仅为9.6 m2/m2,峰值CO产量仅为1.8584 kg/kg.     

无卤阻燃PF/EP/GF布复合材料的固化性能和阻燃性能

采用环氧树脂(EP)作固化剂,2,4,6-三(二甲胺基甲基)-苯酚(DMP30)作固化促进剂改善酚醛树脂(PF)的固化性能,以氢氧化铝和有机磷阻燃剂协同改性其阻燃性能,将其涂覆于玻璃纤维(GF)布上,压制成无卤阻燃PF/EP/GF布复合材料.用傅立叶变换红外光谱(FTIR)仪和差示扫描量热(DSC)仪对无卤阻燃PF/EP/GF布复合材料的固化反应机理、固化反应动力学进行了分析研究,并测试了该复合材料的阻燃性能.结果表明,无卤阻燃PF/EP/GF布复合材料的固化反应表观活化能Ea=75.7 kJ/mol、反应级数n=0.91,起始固化温度、固化峰顶温度、固化终止温度分别为108.6、133.2、152.9℃;当氢氧化铝质量分数为14%、DMP30质量分数为1%、有机磷阻燃剂质量分数为4.8%时,无卤阻燃PF/EP/GF布复合材料的固化性能、阻燃性能均达到较佳状态.     

不同造粒尺寸PEEK/GF复合材料性能研究

采用质量份数比为30∶70的连续玻璃纤维(GF)与聚醚醚酮(PEEK)制备了长度分别为4mm,8mm和12mm的3种不同造粒尺寸PEEK/GF复合材料,研究了不同造粒尺寸对复合材料力学性能及熔融结晶行为的影响,并用扫描电子显微镜观察其断面形貌。结果表明:随着造粒尺寸的增加,GF的剩余长度增加,复合材料储能模量降低,损耗因子(tanδ)降低,力学性能小幅度提高;当造粒尺寸为12mm时,复合材料拉伸强度和弯曲强度分别提高了2.13MPa,1.74MPa,断裂伸长率提高了2.86%,综合力学性能最佳。     

PPS与二乙基次膦酸铝协同阻燃GF增强PBT研究

采用聚苯硫醚(PPS)与二乙基次膦酸铝复配(ALDP),对玻璃纤维(GF)增强聚对苯二甲酸丁二酯(PBT)进行无卤阻燃改性,研究了复配阻燃体系对GF增强PBT阻燃性能和力学性能等的影响。结果表明,ALDP与PPS复配具有明显的协同阻燃效果,且随PPS含量的增加,阻燃GF增强PBT的力学性能呈现先降低后增加的趋势,而热变形温度、热分解温度和高温残留率逐渐提高,最大热分解速率逐渐降低。当添加PPS与ALDP的质量分数分别为10%,15%时,阻燃GF增强PBT的阻燃性能可达到UL94 V–0级(1.6 mm),拉伸强度为97.6 MPa,弯曲强度为149.1 MPa,缺口冲击强度为7.3 k J/m2,热变形温度为210.2℃,失重50%时的热分解温度(T50%)为513.5℃,700℃时的残留率为42.08%,最大热分解速率为9.53%/min。扫描电子显微镜测试表明,PPS的加入可以促进阻燃材料成炭,且对燃烧中形成的炭化层有加固作用,有效阻隔氧气和热量的传递,从而提高阻燃材料的阻燃性能。     

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。