共查询到19条相似文献,搜索用时 140 毫秒
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采用本体聚合技术合成全氘代聚苯乙烯(DPS),所得聚合物分子量约250000,分散度约3,氘代率为98.7%。采用热诱导相分离技术制备全氘代聚苯乙烯泡沫。在室温溶解DPS于溶剂中,然后转入轴向冷却模具,进行单向冷却,直到溶剂完全冷冻,最后取出冷冻样置于冷冻干燥仪中进行冷冻干燥,待溶剂完全脱出后即得泡沫。通过对二恶烷/环己烷混合溶剂相图,以及PS一混合溶剂体系的相图的测定, 相似文献
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介绍了一种利用聚合物和溶剂的相分离,经过冷冻干燥来制备聚合物泡沫(特别是聚苯乙烯类泡沫)的通用技术。采用该技术制备的具有开放状孔洞结构的聚苯乙烯泡沫的密度为0.02~0.1g/cm3,平均孔径为1~20μm,而且泡沫具有各向同性,孔径非常均匀。通过对聚合物泡沫的表征,对影响泡沫形貌和密度的因素,如聚合物/溶剂体系,冷却速率等进行了研究,结果表明:所用溶剂对于该聚合物的Θ温度(溶剂与聚合物作用力为零的温度)必须高于该溶剂的熔点;采用单轴冷却方式可以减小由于溶液中心处和外围处的温差而引起的热应力对泡沫形貌的影响,冷却速率为100℃/min。 相似文献
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以2,3-二甲氧基苯甲醛和联苯胺为原料,在无水甲醇溶剂中合成了一种新的Schiff碱,收率为86.0%.反应的最佳条件是2,3-二甲氧基苯甲醛与联苯胺的比例为3:1,反应时间为1h,反应温度为30℃.这种新的Schiff碱结构利用IR和UV光谱表征. 相似文献
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报道了在水-四氢呋喃组成的混合溶剂中,采用硫酸氢钠催化各种生物质原料(玉米芯、玉米秸秆、麦秆、稻秆和甘蔗渣)制备重要的生物质基平台化学品5-羟甲基糠醛和糠醛的研究. 考察了反应温度(160~200 oC)、反应时间(30~120 min)、水与四氢呋喃的溶剂比例(1:1~1:10)和原料质量分数(2.4wt%~11.1wt%)等反应工艺的影响.在优化的工艺条件下(190 oC, 90 min, 10:1 THF:H2O),转化玉米芯得到了47mol%的HMF和56mol%的糠醛. 此外,原料中的木质素也被有效地转化为有机溶木质素. 相似文献
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在超声波作用下,以浓硫酸为催化剂催化合成乙酸异戊酯.最佳反应条件是:乙酸和异戊醇的摩尔比1:2.2,催化剂用量为1.2mL,反应时间为20min,超声波输出功率为90W.在此反应条件下,酯产率为78.5%. 相似文献
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采用红外显微图像技术对单层掺硫空心微球上出现的不均匀结构进行了表征分析,证明了不均匀结构的产生来源于掺硫剂PSS(聚苯乙烯磺酸钠)。同时对PSS的成膜性能进行了研究,并使用红外显微图像技术和偏光显微镜对PSS平面薄膜进行表征,结果表明,掺硫剂PSS成膜性能较差,薄膜表面存在分子有序化聚集体和结晶现象。热处理结果显示PSS薄膜与聚苯乙烯薄膜热性能相差较大,易产生脆性开裂并从聚苯乙烯表面剥离,说明PSS不适合于高掺硫量微球制备。 相似文献
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CdS纳米粒子的微波法制备及其光谱特性研究 总被引:1,自引:0,他引:1
用微波法以硫代乙酰胺为硫源,成功合成了CdS纳米粒子。透射电子显微镜(TEM)对合成的CdS纳米粒子的表征结果为粒径约12 nm, 粒径分布较为均匀,分散性较好。研究了微波功率、pH值、反应时间等因素对其吸收光谱,荧光光谱和粒径的影响。结果表明,在微波功率为30%、初始反应pH 9.0、微波反应时间为25 min时,可合成质量较高的CdS纳米粒子。比较了以硫代乙酰胺、硫脲和硫化钠为硫源合成的CdS纳米粒子,结果表明,以硫代乙酰胺为硫源合成的CdS纳米粒子荧光带边发射强,缺陷发射弱,荧光性质较好;而以硫脲为硫源合成的CdS纳米粒子荧光边带发射弱;以硫化钠为硫源合成的CdS纳米粒子荧光以缺陷发射为主。铜离子在6.4~512 μg·L-1范围内对该纳米粒子荧光的猝灭呈现良好线性, 可用于痕量铜离子的测定。 相似文献
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N. V. Ulitin T. R. Deberdeev A. A. Berlin 《Russian Journal of Physical Chemistry B, Focus on Physics》2014,8(2):227-232
Numerical experiments are used to examine how the molecular mass and polydispersity index of polystyrene synthesized by controlled addition-fragmentation radical polymerization depend on various control parameters of the process, such as the temperature and initial concentrations of monomer, initiator, and reversible chain transfer agent. 相似文献
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Preparing Cu<sub>2</sub>ZnSnS<sub>4</sub> films using the co-electrodeposition method with ionic liquids 下载免费PDF全文
Cu2ZnSnS4(CZTS) films are successfully prepared by co-electrodeposition in aqueous ionic solution and sulfurized in elemental sulfur vapor ambient at 400 C for 30 min using nitrogen as the protective gas.It is found that the CZTS film synthesized at Cu/(Zn+Sn)=0.71 has a kesterite structure,a bandgap of about 1.51 eV,and an absorption coefficient of the order of 10 4 cm 1.This indicates that the co-electrodeposition method with aqueous ionic solution is a viable process for the growth of CZTS films for application in photovoltaic devices. 相似文献
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Raspberry-shaped composite particles with polystyrene (PSt) as core and poly(n-butyl acrylate-co-acrylic acid) (P(BA–AA)) as corona were synthesized via emulsion polymerization. The random copolymer, P(BA–AA), was pre-prepared and used as a polymeric surfactant, its emulsifying properties adjusted by changing the mass ratio of BA and AA. The morphology of the resulting core–corona composite particles, P(St/P(BA–AA)), could be regulated and controlled by varying the concentrations of P(BA–AA) or the mass ratio of BA:AA in P(BA–AA). The experimental results indicate that 3.0–6.0 wt% of P(BA–AA) is required to obtain stable composite emulsions, and P(BA–AA) with a mass ratio of BA:AA = 1:2 is able to generate distinct core–corona structures. A mechanism of composite particle formation is proposed based on the high affinity between the PSt core and the hydrophobic segments of P(BA–A). The regular morphology of the colloidal film is expected to facilitate potential application of core–corona particles in the field of light scattering. Furthermore, the diversity of core–corona particles can be expanded by replacing P(BA–AA) corona particles with other amphiphilic particles. 相似文献
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采用播种生长法制备了粒径为330 nm的单分散胶体二氧化硅(SiO2),并对单分散的SiO2颗粒表面进行改性,以提高颗粒对苯乙烯单体的亲和力.然后通过垂直沉积法组装出SiO2胶粒晶体模板.依靠毛细管力将苯乙烯前驱物快速填充进模板颗粒的间隙,加热原位聚合 ,用氢氟酸去除模板后制得三维有序大孔聚苯乙烯.扫描电子显微镜结果显示,所合成的孔材料高度有序,孔腔尺寸约为210 nm,孔腔之间由较小孔窗连接,形成非常开放的通道网络 .
关键词:
三维有序大孔材料(3DOM)
聚苯乙烯
模板
二氧化硅 相似文献
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Cu2ZnSnS4(CZTS) films are successfully prepared by co-electrodeposition in aqueous ionic solution and sulfurized in elemental sulfur vapor ambient at 400 C for 30 min using nitrogen as the protective gas.It is found that the CZTS film synthesized at Cu/(Zn+Sn)=0.71 has a kesterite structure,a bandgap of about 1.51 eV,and an absorption coefficient of the order of 10 4 cm 1.This indicates that the co-electrodeposition method with aqueous ionic solution is a viable process for the growth of CZTS films for application in photovoltaic devices. 相似文献