阻燃增强PBT/AS合金的性能研究

通过双螺杆挤出机制备了一系列阻燃增强聚对苯二甲酸丁二醇酯(PBT)/苯乙烯-丙烯腈共聚物(AS)合金,研究了PBT与AS配比对合金的力学性能、阻燃性能和成型收缩率的影响,并用差示扫描量热(DSC)和热失重(TG)对材料的熔融行为、结晶行为和热稳定性能进行了分析。结果表明,PBT/AS配比对阻燃增强PBT/AS合金的拉伸强度、弯曲强度和阻燃性能影响较小,但AS用量的增加会明显降低材料的缺口冲击强度、热变形温度和纵向收缩率;DSC和TG测试表明,PBT/AS配比对阻燃增强PBT/AS合金的熔融温度、结晶温度、结晶速度和结晶度均无影响,材料的熔融焓、结晶焓和热稳定性随AS用量增加逐渐下降。     

ALPi和MPP协同阻燃PBT的研究

采用二乙基次磷酸铝(ALPi)作为阻燃剂、三聚氰胺聚磷酸盐(MPP)为协效剂、聚对苯二甲酸丁二醇酯(PBT)为基体,通过熔融共混,制得阻燃PBT。通过极限氧指数(LOI)和垂直燃烧(UL-94)研究了阻燃PBT的阻燃性能,通过热重分析(TGA)研究了阻燃PBT的热分解过程,采用扫描电镜(SEM)观察阻燃PBT燃烧炭层的形貌。结果表明,ALPi和MPP质量比为2∶1时,阻燃PBT的阻燃效果最好,LOI达到31%,垂直燃烧达到UL-94V-0级。TGA表明,复配阻燃体系的加入促进了PBT的提前分解,有利于在PBT表面形成保护性炭层,从而提高PBT的阻燃性。阻燃PBT燃烧炭层扫描电镜说明,复配阻燃体系能增加炭层密度,提高阻燃效果。     

玻纤增强PTT及其性能研究

初步研究了聚对笨二甲酸丙二酯(PTT)固相聚合及其玻璃纤维(GF)增强工艺,探讨了PTT的热稳定性及GF含量和树脂特性粘度对GF增强PTT性能的影响,并对PTT与聚对苯二甲酸丁二酯(PBT)增强前后的性能进行了比较。结果表明,添加GF可大幅度提高GF增强PTT的力学性能和热性能;树脂特性粘度对未增强PTT缺口冲击强度和热变形温度的影响较为明显,但对GF增强PTT的性能影响较小;高粘度PTT的热稳定性较差;GF增强PTT、PBT的综合性能相差不大。     

高灼热丝阻燃玻纤增强聚丙烯的研究

采用双螺杆挤出机共混的方法分别制备了氮–磷膨胀型阻燃聚丙烯(PP)、溴–锑阻燃PP、氮–磷–溴–锑复配阻燃PP和氮–磷–溴–锑复配阻燃玻纤(GF)增强PP,通过力学性能测试、垂直燃烧测试、灼热丝燃烧测试、扫描电子显微镜和热重分析研究了阻燃PP的力学性能、阻燃性能和热性能。结果表明,不同阻燃体系阻燃PP的垂直燃烧等级均达到V–0级,灼热丝引燃温度均高于790℃;氮–磷–溴–锑复配阻燃剂的阻燃效果最优,其阻燃PP的灼热丝引燃温度可达850℃以上;添加10%的GF可有效提高氮–磷–溴–锑复配阻燃PP的力学性能,其拉伸强度、悬臂梁缺口冲击强度、弯曲强度和弯曲弹性模量分别为纯PP的1.59倍、1.56倍、1.93倍和1.88倍,同时灼热丝引燃温度仍在850℃以上,残炭率为23.6%。     

GF增强PBT/PET合金的性能和外观

在质量分数30%玻璃纤维(GF)增强聚对苯二甲酸丁二酯(PBT)的基础上,通过引入不同含量的聚对苯二甲酸乙二酯(PET)组分制备了不同PBT/PET比例的合金。系统研究了PET含量对合金的傅立叶变换红外光谱(FTIR)、熔融结晶行为、力学性能、流动性能及外观的影响。实验结果显示:PET引入后,合金的FTIR谱图中出现了PET特征吸收峰(1 341cm-1);由于发生了部分酯交换反应,合金中PBT和PET的结晶能力减弱;PET的加入提高了GF增强PBT的力学性能,拉伸强度和弯曲强度分别能够提高10.1%和8.9%;相较于GF增强PBT,GF增强PBT/PET合金的流动性有所提高;同时,GF增强PBT/PET合金注塑制品的外观得到显著改善,样品表面浮纤面积占比由GF增强PBT的7.6%降低至GF增强PBT/PET合金(PET质量分数为40%)的0.4%。当PET质量分数为20%～35%时,所得PBT/PET合金同时具备优异的力学性能和良好的外观。     

两步法挤出无卤阻燃增强PBT的研制

对比了两步法挤出造粒的无卤阻燃增强聚对苯二甲酸丁二酯( PBT)与一步法挤出造粒的无卤阻燃增强PBT的力学性能、阻燃性能、电性能.结果表明,在相同配方条件下,两者的综合力学性能相当;但两步法的无卤阻燃增强PBT的电性能和阻燃性能明显优于一步法.     

次磷酸铝/磷腈衍生物协效阻燃PBT的性能研究

将次磷酸铝(AHP)与六对醛基苯氧基环三磷腈(HAPCP)复配后添加到聚对苯二甲酸丁二醇酯(PBT)中制备阻燃PBT材料,通过氧指数和垂直燃烧(UL 94)测试研究了材料的阻燃性能,通过热重分析(TGA)技术研究了材料的热稳定性及成炭性能,同时还研究了AHP与HAPCP的质量比对PBT材料阻燃性能的影响。结果表明:AHP用量为18%时,PBT可通过UL 94V-0测试,氧指数为23.8%;而AHP与HAPCP以15:1复配后用于PBT的阻燃,当复合阻燃剂用量为16%时,PBT材料就能通过UL 94V-0测试,氧指数达到了25.3%,表明HAPCP与AHP对PBT具有很好的协效阻燃作用。阻燃剂AHP和HAPCP的加入使PBT材料的起始热分解温度由336℃降至324℃,但材料在700℃的残炭率由0.7%提高到15.9%,表明阻燃剂的加入促进了材料提前降解成炭,形成的炭层能有效阻止氧气和热量进入材料内部,抑制可燃气体的逸出,阻止了基体材料的进一步降解和燃烧,从而提高了材料的阻燃性能。     

O–VMT和二乙基次磷酸铝对PBT/GF的阻燃作用

研究了有机蛭石(O–VMT)和二乙基次磷酸铝(ADP)对玻纤(GF)增强聚对苯二甲酸丁二酯(PBT)(PBT/GF)的阻燃作用,对复合材料的极限氧指数(LOI)和UL94阻燃等级进行测试,并用热失重和锥形量热仪进行分析。结果发现,ADP可以很好阻燃PBT/GF,加入19%的ADP,复合材料的LOI为33.5%,阻燃达到UL941.6 mm V–0级,相对PBT/GF,其点燃时间、火灾性能指数(FPI)有所提高,热释放速率峰值(PHRR)、平均热释放速率(AHRR)、总热释放量(THR)及总生烟量(TSR)有所降低。同时加入15%的ADP和2%的O–VMT,复合材料的PHRR,AHRR,THR和TSR相对单独添加17%ADP的材料,分别降低12.8%,9.5%,4.5%和15.9%,FPI提高15.4%,LOI和UL94阻燃也对应提高,O–VMT和ADP在PBT/GF中有协同阻燃作用。     

协效阻燃剂和增韧剂对卤素阻燃玻纤增强PBT材料性能的影响

使用溴化环氧树脂作为主阻燃剂,采用熔融共混法制备了玻璃纤维增强阻燃聚对苯二甲酸丁二酯(PBT)复合材料。分析讨论了五种协效阻燃剂(三氧化二锑、无水硼酸锌、锑酸钠、水合铝酸碳酸镁、水合铝酸碳酸钙)和增韧剂对材料物理力学性能、阻燃性能和热稳定性的影响。结果表明,三氧化二锑的协效阻燃效果最好,但是使得材料的力学性能和热稳定性降低,锑酸钠的阻燃效果略低于三氧化二锑但是对材料的力学性能和热稳定性影响较小。选择锑酸钠作为协效阻燃剂,加入少量的水合铝酸碳酸钙有利于提高材料的拉伸和弯曲强度、热变形温度及阻燃性能。丙烯酸酯-有机硅共聚物对材料的增韧效果较弱但是不会影响材料的阻燃等级,乙烯-丙烯酸甲酯-甲基丙烯酸缩水甘油酯共聚物的增韧效果最优,但是会降低材料的阻燃等级。     

层状阻燃结构对PBT/IFR复合材料性能的影响

通过熔融共混和模压成型技术制备了聚对苯二甲酸丁二酯(PBT)/膨胀型阻燃剂(IFR)共混和层状复合材料,其中层状复合材料为3层阻燃结构,内层为非阻燃层(纯PBT),内层外面两层为阻燃层(PBT/IFR)。通过UL94垂直燃烧、极限氧指数(LOI)以及拉伸和冲击性能测试对比分析了两种复合材料的阻燃性能和力学性能。结果表明,与PBT/IFR共混复合材料相比,PBT/IFR层状复合材料的阻燃性能提高幅度更大,虽然低IFR含量下其力学性能低于共混复合材料,但随着IFR含量增加,力学性能下降幅度更小。当层状复合材料中的阻燃层/非阻燃层/阻燃层的厚度比为1.5 mm/1 mm/1.5 mm,即IFR质量分数为22.5%时,其拉伸强度、断裂伸长率和冲击强度与相同IFR用量下的共混复合材料相当,而阻燃性能与IFR质量分数为30%的共混复合材料相当,其UL 94阻燃等级达到V–0级,LOI提高到24.4%。这表明,采用层状阻燃可控受限结构,可在较低的IFR用量下更好地提高PBT/IFR复合材料的阻燃性能,同时减缓了力学性能下降的幅度。     

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。