粉末天然橡胶制备的影响因素分析

采用直接凝聚工艺对天然胶乳进行凝聚成粉,研究了隔离剂的种类、隔离剂的用量、凝聚剂、凝聚温度、搅拌转速、熟化条件等对凝聚成粉效果的影响。结果表明,当采用复合隔离剂2.5份,凝聚剂用量为12份,凝聚温度在30～40℃,搅拌转速为450 r/min时,天然胶乳成粉效果较好,98%的粉末胶粒粒径小于0.45 mm;粉末天然橡胶（PNR）的力学性能与天然橡胶（NR）基本相当。     

填充型粉末丁苯橡胶的开发

确定了超细碳酸钙填充型粉末丁苯橡胶（PSBR）的制备工艺，研究了影响凝聚粉末化效果的因素，结果表明，影响粉末化效果的主要因素是包覆剂用量、凝聚条件、搅拌转速，次要因素是凝聚温度、干燥方式。适宜的粉末化条件是包覆剂用量为10份，将凝聚剂加入m(胶）：m(水）=8.5:100的凝聚体系中，搅拌转速为400-500r/min(3L凝聚釜），凝聚温度不小于40℃，湿粉采用闪蒸干燥方式干燥。     

高门尼黏度粉末丁苯橡胶1712工业化技术开发

以丁苯胶乳1712为原料,在3 kt/a粉末丁苯橡胶(PSBR)装置上进行了PSBR 1712的试生产。研究了搅拌转速、凝聚剂用量、隔离剂用量、凝聚温度以及成型剂加入温度对PSBR 1712成粉率的影响。结果表明,在凝聚搅拌转速为100 r/m in、凝聚温度为40~60℃、凝聚剂用量为10~20份、隔离剂用量为5~10份、70℃加入成型剂的条件下,可以生产出粒径不大于1.25 mm、橡胶质量分数不小于90%和成粉率达到96.0%以上的PSBR 1712。     

粉末氯丁橡胶-244的制备及与块状氯丁橡胶的比较

以氯丁胶乳为原料,采用直接凝聚法制备粉末氯丁橡胶(PCR-244),研究了体系pH值、凝聚剂和隔离剂用量、凝聚温度、搅拌转速对PCR-244凝聚效果的影响,并与块状氯丁橡胶进行了对比.结果表明,在体系pH值为11～13、凝聚剂和隔离剂用量分别为20份和10～15份以及凝聚温度为20～25℃、搅拌转速为80～100 r/min的条件下,能得到平均粒径小于0.80 mm、成粉率达100%的PCR.相同条件下,PCR比块状氯丁橡胶的溶解速率大大提高,但二者溶解后的溶液黏度和剥离强度相近.PCR-244仅仅改变了氯丁橡胶的形态,其内部主要结构与块状氯丁橡胶相似.     

高分子包覆凝聚法制备粉末丁苯橡胶

以丁苯胶乳为原料,脂肪酸类化合物与硅化合物为隔离剂,NaCl、ZnSO4和CaCl2混合溶液为凝聚剂,采用高分子包覆正凝聚法制备了粉末丁苯橡胶（PSBR）,研究了包覆剂的玻璃化转变温度及其用量、隔离剂种类、凝聚剂种类、搅拌转速、凝聚温度,凝聚方式及设备、熟化温度及时间、干燥方式及设备对PSBR平均粒径的影响。结果表明：当包覆剂玻璃化转变温度为60℃,包覆剂用量为2．5份,搅拌转速为400r／min,凝聚温度为60℃,熟化温度为80—95℃,熟化时间为15—30min时,以室温自然干燥方式制备的98％的PSBR粒径小于0．9mm。     

MBS树脂合成技术的中试研究(Ⅲ)MBS胶乳的凝聚

阐述了聚合物乳液的凝聚机理和MBS接枝胶乳的凝聚工艺,在MBS胶乳凝聚小试研究和MBS接枝胶乳中试研究的基础上进行了MBS接枝胶乳凝聚的中试研究,着重研究了凝聚剂种类、用量和加料方式以及凝聚温度、水胶比等对MBS粉料堆密度和粒度分布的影响,确定了MBS胶乳的凝聚工艺,为5 000 t/a MBS树脂生产装置提供了设计依据.     

ACR胶乳凝聚过程的研究

以丙烯酸酯（ACR）聚合物胶乳凝聚过程中粒径的变化表征凝聚效果，探讨在凝聚剂作用下的凝聚机理，研究凝聚剂、凝聚温度、搅拌转速、搅拌时间和胶乳固含量等条件对凝聚过程的影响规律，为优化工艺条件，制备大小均匀、形态较为规整的凝聚颗粒，实现ACR胶乳凝聚的工业化提供基础。     

ABS/SBR共混体系的动态硫化技术及工艺研究

研究了动态硫化技术对丙烯腈-丁二烯-苯乙烯共聚物/丁苯橡胶(ABS/SBR)共混物性能的影响,讨论了硫化工艺条件及不同硫化剂用量对ABS/SBR共混体系的力学性能、耐热性及加工流动性的影响.结果表明,当硫化温度为180℃,螺杆转速为120 r/min时,体系混炼效果最好；在一定范围内,随着硫化剂用量的增加,体系的力学性能逐渐增强,当硫磺用量为0.6 phr时,体系的综合性能最佳.     

硅藻土基粉体凝聚剂的制备及对煤泥水的处理

为提高煤泥水的沉降效果,利用硅藻土及FeCl3制备了硅藻土基粉体凝聚剂,采用正交试验对硅藻土基粉体凝聚剂制备过程的三个主要影响因素:焙烧温度、m(FeCl3)∶ m(G)(质量比)(G表示硅藻土)和焙烧—酸浸顺序进行试验研究,并对其作用机理进行初步分析.结果表明:焙烧温度为500℃,m(FeCl3)∶ m(G)为=1∶5,先焙烧再酸浸为最佳工艺条件.利用最佳工艺条件制备的硅藻土基粉体凝聚剂对煤泥水进行了凝聚试验,当煤泥水质量浓度为60 g/L,体积为100 mL,硅藻土基粉体凝聚剂添加量为0.5g时,其透光率可以达到78.95％,凝聚效果最佳.     

磷石膏复分解制硫酸铵的工艺研究

采用单因素试验,进行了以磷石膏为原料复分解反应制备硫酸铵的试验,考察了反应时间、反应温度、加料速度、液固比、物料比[n(CO2-3)/n(SO2-4)]和搅拌器转速对反应的影响.通过正交试验优选,确定了最佳工艺条件:反应时间为100 min,反应温度为45℃,搅拌器转速为150 r/min,物料比[n(CO2-3)/n(SO2-4)]为1.15,液固比(质量计)为2.9,加料速度为36g/min.在最佳工艺条件下,磷石膏中SO2-4的平均转化率为98.98%.     

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。