不同激光蚀刻技术对陶瓷与复合树脂材料粘接强度的影响研究

分析了不同激光蚀刻技术对陶瓷与复合树脂材料粘接强度的影响。通过扫描电镜观测瓷片表面微观形貌变化,利用光干涉三维表面形貌测量系统测量瓷片表面粗糙度,应用万能力学试验机测试瓷片与树脂柱粘接强度。相较于control组与HF组,NY组与EY组能够有效改变瓷片表面微观形貌,提升瓷片表面粗糙度,增加瓷片与树脂柱粘接强度。综合上述实验数据发现,相较于EY组,NY组瓷片表面微观形貌改变度较大,瓷片表面粗糙度、瓷片与树脂柱粘接强度数值均较高,说明Nd:YAG激光蚀刻技术应用效果优于Er:YAG激光蚀刻应用效果。充分证实Nd:YAG激光蚀刻技术更能提升陶瓷与复合树脂材料粘接强度。     

气体加压技术对两步法自酸蚀粘接系统树脂牙本质粘接效果的影响

探讨使用不同压力气体吹拂两步法自酸蚀粘接剂对树脂牙本质粘接界面微观形貌及微拉伸粘接强度的影响。20颗离体的完整无龋第3磨牙去除冠釉,按粘接过程中气体吹拂处理方法不同随机分为4组(处理剂和粘合剂均轻吹;处理剂强吹,粘合剂轻吹;处理剂轻吹,粘合剂强吹;处理剂和粘合剂均强吹。轻吹气压为0.1MPa,强吹气压为0.3 MPa),每组5颗牙。各组粘接完成后,37℃水浴24 h,每颗牙切出1片薄片状试件利用场扫描电子显微镜(SEM)观察4组粘接界面微观形貌(n=5),另外每颗牙制成8根长方体形试件测试微拉伸强度(μTBS)(n=40)。SEM观察显示,第1组的粘接剂层最厚,树脂突最短小稀疏;第2组和第3组的粘接剂层较薄,树脂突更长更致密更均匀;第4组的粘接剂层最薄,但是树脂突更长更致密更均匀。第2组的μTBS最高(41.32±3.76)MPa,其次为第3组(31.17±4.80)MPa、第1组(26.24±5.21)MPa,第4组最低(14.89±2.31)MPa。在两步法自酸蚀粘接中,采用气体加压技术吹拂处理剂可显著提高树脂牙本质粘接强度。     

气体吹拂压力对两步法自酸蚀粘接剂老化粘接性能的影响

探讨了气体吹拂压力对两步法自酸蚀粘接剂SE Bond老化后微拉伸粘接强度的影响。20颗离体的完整无龋第3磨牙去除冠釉,按粘接过程中气体吹拂处理方法不同随机分为4组(处理剂轻吹+粘合剂轻吹;处理剂强吹+粘合剂轻吹;处理剂轻吹+粘合剂强吹;处理剂强吹+粘合剂强吹。轻吹气压为0.1 MPa,强吹气压为0.3 MPa。吹拂时间均为5 s,吹拂距离均为1 cm),每组5颗牙。各组粘接完成后,37℃水浴24 h,冷热循环5 000次,之后测试微拉伸粘接强度(μTBS)(n=45)。试验结果表明,第2组(处理剂强吹+粘合剂轻吹)的μTBS相对最高,为(40.37±11.42)MPa。应用两步法自酸蚀粘接剂SE bond时,采用气体加压技术吹拂处理剂联合常规气压轻吹粘合剂可显著提高树脂牙本质的粘接耐久性。     

苯并噁嗪树脂基复合材料的制备及性能表征

本文采用氧等离子体对碳纤维表面进行活化,后用偶联剂接枝的方法对碳纤维表面进行处理。按照GB3357-82和GB3356-82,对复合材料层间剪切强度和弯曲强度进行测试并研究等离子体处理及偶联剂接枝对碳纤维/苯并噁嗪(Polybenzoxazine,PBOZ)复合材料界面粘接性的影响。通过XPS,SEM对碳纤维表面及复合材料断裂面形貌进行测试,分析界面粘接机制。研究表明,氧等离子体处理使碳纤维表面粗糙度和活性含氧基团含量增加,增加了纤维与树脂之间的粘接性;氧等离子体处理后再进行偶联剂接枝,碳纤维表面的含氧官能团增加,浸润性得到改善,提高了碳纤维/PBOZ复合材料界面粘接性能。     

自粘性流动树脂对牙本质粘接强度的研究

目的对比新型自粘性流动树脂Constic与目前常用的自酸蚀粘结剂搭配普通复合树脂对牙本质的粘接强度,评估自粘性流动树脂Constic的粘接性能能否满足临床需要。方法收集新鲜拔出的人类磨牙60颗,随机分为3组(A组,B组,C组):A组为自粘性流动树脂Constic、B组为一步法自酸蚀粘结剂幻彩-bond搭配普通流动树脂Filtek Supreme XT Flowable、C组为两步法自酸蚀粘结剂Clearfil SE-Bond搭配Filtek Supreme XT Flowable。测试粘接试样剪切粘接强度并对测试结果进行单因素方差分析(one-way ANOVA,LSD)分析。然后在体式显微镜下放大至50倍进行断裂面观察并进行断裂类型统计。结果3组剪切粘接强度分别为:9.15±2.33MPa(A组),10.79±2.37MPa(B组),13.89±2.56MPa(C组)。A组剪切粘接强度与B组之间的差异无统计学意义(P0.05),但均低于C组(P0.05)。A组和B组主要发生的是粘附破坏,C组以混合断裂为主。结论自粘性流动树脂Constic与一步法自酸蚀粘结剂相似,可满足临床需要。     

纳米颗粒粒径对等离子喷涂法制备氧化锆纳米涂层的影响

利用扫描电镜(SEM)、场发射扫描电镜(FESEM)、透射电镜(TEM)、比表面积吸附法(BET)等分析测试技术,研究了3种不同纳米尺寸氧化锫粉粒的造粒性能、沉积效率以及对等离子喷涂涂层晶粒大小、涂层熔融性能、结合强度的影响.结果表明:纳米氧化锆粉体一次颗粒粒径大小显著影响纳米粉体的喷雾造粒性能、沉积效率、涂层表面粗糙度、涂层晶粒粒径和结合强度大小.本试验中,利用颗粒一次粒径范围为50～70 nm的纳米氧化锆粉体,等离子喷涂制备了晶粒粒径范围为80～120 nm,沉积效率为43%,涂层表面粗糙度为5.92 μm,结合强度为27 MPa的纳米结构氧化锆涂层.     

碳纤维表面处理对液体成型碳纤维增强MC尼龙复合材料力学性能的影响

本论文采用真空辅助树脂灌注成型工艺(VARI),通过己内酰胺原位阴离子聚合的方法制备了连续碳纤维增强浇铸(MC)尼龙的复合材料,并系统研究了丙酮去浆处理、气相氧化处理、偶联剂处理和火焰处理四种不同碳纤维织物表面处理方式的碳纤维表面的O/C比和微观形貌以及复合材料的力学性能、表面形貌和碳纤维体积分数。结果表明:对碳纤维表面进行偶联剂涂层处理,此碳纤维制备的复合材料的力学性能较其他处理方式的碳纤维制备的复合材料而言力学性能最优,其拉伸强度达到595.5 MPa,弯曲强度达到330.7 MPa,层间剪切强度达到30.6 MPa;此条件下碳纤维表面的O/C比达到44.51%,复合材料的碳纤维体积分数达到51.4%。     

PET薄膜表面性能及其与紫外光固化涂层粘接性能相关性研究

通过粘结性能实验研究了表面处理方法对PET薄膜/紫外光固化涂层体系粘接性能的影响,结果表明:表面处理提高了PET薄膜/涂层体系粘接强度。研究了PET表面处理对PET表面性能如表面形貌、光泽度(粗糙度)、表面张力、表面官能团含量的影响,结果表明:PET薄膜经电晕处理后,其表面粗糙度有增大的倾向,而涂层处理对PET薄膜表面粗糙度无影响;经电晕处理和底涂处理后,PET薄膜表面张力均有增加,底涂处理提高PET薄膜表面张力的幅度更大。研究了PET薄膜表面性能与剪切强度的关系,发现PET薄膜/涂层粘接体系剪切强度τ与PET薄膜表面张力γ具有线性关系。     

偶联剂在乙烯基酯树脂/SiC复合材料中的应用

为了提高乙烯基酯树脂与碳化硅(SiC)颗粒间的粘接强度，试验采用偶联剂KH-570来改善材料的复合界面。结果表明：加入一定量的偶联剂KH-570，可显著地提高乙烯基酯树脂与SiC颗粒之间的粘接强度（包括剪切强度、拉伸强度及弯曲强度）及耐磨性，并确定出了乙烯基酯树脂结合SiC耐磨涂层中KH-570的最佳加入量为1.5%，较合适的使用方法为迁移法。     

改善钛合金与J-262发泡胶相容性的方法研究

对钛合金表面进行吹砂处理,研究了不同粗糙度对钛合金与J-262发泡胶相容性的影响。讨论了实际应用中钛合金吹砂后外置时间对相容性的影响,提出了采用与J-262发泡胶相同体系的J-355底胶对吹砂后钛合金表面进行保护,以解决实际工程应用中钛合金外置时间较长影响相容性的问题。研究结果表明:粗糙度控制在Ra=(3.0±0.3)时,钛合金与J-262发泡胶的相容性较好,其剪切强度为2.27 MPa;钛合金表面吹砂后并喷涂J-355底胶,可以提高钛合金与J-262发泡胶的相容性,其剪切强度为2.67 MPa,外置10 d后仍有较好的相容性,其剪切强度为2.20 MPa。     

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。