Microencapsulation of stearic acid with polymethylmethacrylate using iron (Ⅲ) chloride as photo-initiator for thermal energy storage

Aiming to identify the validity of fabricating microencapsulated phase change material (PCM) with polymethylmethacrylate (PMMA) by ultraviolet curing emulsion polymerization method using iron (Ⅲ) chloride as photoinitiator,SA/PMMA microcapsules were prepared and various techniques were employed to determine the ignition mechanism,structural characteristics and thermal properties of the composite.The results shown that the microcapsules containing SA with maximum percentage of 52.20 wt％ formed by radical mechanism and only physical interactions existed in the components both in the prepared process and subsequent use.The phase change temperatures and latent heats of the microencapsulated SA were measured as 55.3 ℃ and 102.1 J.g-1 for melting,and 48.8 ℃ and 102.8 J.g-1 for freezing,respectively.Thermal gravimetric analysis revealed that SA/PMMA has good thermal durability in working temperature range.The results of accelerated thermal cycling test are all shown that the SA/PMMA have excellent thermal reliability and chemical stability although they were subjected 1000 melting/freezing cycles.In summary,the comparable thermal storage ability and good thermal reliability facilitated SA/PMMA to be considered as a viable candidate for thermal energy storage.The successful fabrication of SA/PMMA capsules indicates that ferric chloride is a prominent candidate for synthesizing PMMA containing PCM composite.     

不同成核剂对Na_2HPO_4·12H_2O相变过冷性能的影响

以Na_2HPO_4·12H_2O作为相变材料,研究不同的成核剂对其过冷度的影响。结果显示,Na_2B_4O_7·10H_2O、Na_2SiO_3·9H_2O、Al_2O_3都能有效减低其过冷度,其中Al_2O_3效果最好,2%的Al_2O_3可以将Na_2HPO_4·12H_2O的过冷度降低至2.2℃,同时可延长放热时间。多次循环实验显示,添加2%Al_2O_3的Na_2HPO_4·12H_2O的相变温度和相变潜热变化很小,稳定性较好。     

(C_4H_(10)N_2H)_3HSiMo_(12)O_(40)纳米颗粒的摩擦学研究

在醇-水体系中,以H4S iMo12O40和哌嗪为原料制备了组成为(C4H10N2H)3HS iMo12O40的纳米颗粒,以透射电子显微镜(TEM)、扫描电子显微镜(SEM)、X射线粉末衍射仪(XRD)、傅立叶变换红外光谱仪(FT-IR)、紫外可见分光光度计(UV)、热分析仪(TG-DTA)等测试手段,对纳米颗粒的形貌、组成和结构进行了表征,并在机械式四球长时抗磨损试验机上考察了其摩擦学性能。分散型实验结果表明,化合物在有机溶剂中良好分散(除乙醚外),红外/紫外光谱和X射线粉末衍射表明,所合成的纳米颗粒具有杂多酸Keggin骨架结构无机核,透射电镜分析表明,颗粒平均粒径约为10 nm,热分析显示分解温度范围为200~425℃,作为新型有机/无机复合纳米润滑油添加剂,最佳添加浓度为0.35%时,在测试条件为负荷294 N,时间30 m in,转速1450 r/m in条件下,使磨斑直径减小22.7%,摩擦系数减小14%。     

Nd2（C7H4NO4）2(SiW12O40)·18H2O的合成及其光电性能的研究

以硅钨酸和2,3-吡啶二羧酸为配体合成了一种新型的配合物Nd2(C7H4NO4)2(SiW12O40)·18H2O,并对其进行了元素分析、红外光谱、紫外光谱、荧光光谱、热重分析和电化学分析等一系列表征。结果表明:配合物在261nm处具有较强的紫外吸收;在361nm处进行荧光激发,分别在431nm和480nm处得到两个强度不同的荧光发射峰;具有较好的热稳定性;在-0.3~0.3V的电势范围具有电化学活性。     

层状纳米晶Mn_3(PO_4)_2·3H_2O的室温固相合成及表征

以MnSO4.H2O和K2HPO4.3H2O为原料,在表面活性剂聚乙二醇(PEG)-400的存在下,通过室温下研磨反应物进行固相反应,然后在室温下保持混合物5 h,接着用水洗去混合物中的可溶性无机盐并于80℃下干燥,即得层状纳米晶Mn3(PO4)2.3H2O。产品Mn3(PO4)2.3H2O和它的热分解产品用TG/DTA,IR,XRD,SEM,UV-V is和磁化率表征。结果表明,80℃下干燥5 h所得的产品具有高的结晶度[空间群Pmnm(59)],其平均一次粒径为19 nm,平均夹层距离为0.811 2 nm。产品Mn3(PO4)2.3H2O的磁化率分析表明该化合物具有铁磁性质,其铁磁排序温度约为17 K。     

晶体化合物(n-C_(12)H_(25)NH_3)_2CdCl_4(s)的制备及热化学研究

用水热合成法合成了晶体化合物(n-C12H25NH3)2Cd Cl4(s);根据热化学原理计算了化合物(n-C12H25NH3)2Cd Cl4(s)的晶格能为889.81 k J·mol-1。利用等温溶解-反应热量计,得到了该化合物的标准的摩尔焓:[(n-C12H25NH3)2Cd Cl4,s]=-(1836.23±7.95)k J·mol-1。     

H4GeW12O40/Cu3(BTC)2催化Biginelli反应合成3,4-二氢嘧啶-2(1H)-酮衍生物

采用浸渍法以金属有机骨架Cu_3(BTC)_2负载锗钨酸(H_4GeW_(12)O_(40))制备H4Ge W_(12)O_(40)/Cu_3(BTC)_2催化剂,并用该催化剂催化芳醛、尿素和乙酰乙酸乙酯通过"一锅法"Biginelli缩合反应,以无水乙醇为溶剂,合成6种3,4-二氢嘧啶-2(1H)-酮衍生物;通过熔点的测定,IR,1H NMR和MS等对产物3,4-二氢嘧啶-2(1H)-酮衍生物进行表征。结果表明:在芳醛用量为0.04 mol,n(芳醛)∶n(乙酰乙酸乙酯)∶n(尿素)=1∶1.5∶1.5,催化剂的用量占反应物料总质量的4.0%,反应温度为90℃,反应时间为90 min的条件下,目标产物收率可达63.0%~76.3%。     

Sodium sulfonate functionalized magnetic Fe3O4@SiO2 towards the preparation of sorbent for Cu(Ⅱ) removal

通过化学一步共沉淀法制备了疏水性的Fe3O4纳米粒子,然后采用反相微乳液法制备出分散性良好、粒径均匀的Fe3O4@SiO2复合磁性纳米粒子,紧接着用2-(4-氯磺酰苯基)乙基三甲氧基硅烷对其表面进行修饰,最终再经过1.0 M NaCl溶液处理得到富含磺酸基官能团磁性纳米吸附剂(Fe3O4@SiO2-SO3Na).通过透射电镜(TEM)、X射线衍射(XRD)、红外光谱(FT-IR)、振动样品磁强计(VSM)等对其进行了表征,着重研究了其对水溶液中Cu(Ⅱ)离子的吸附性能.结果表明,溶液的pH值能显著影响吸附剂对Cu(Ⅱ)离子的吸附效果,其中pH值为5.1时吸附效果最佳,即Cu(Ⅱ)从初始的20mg·L-1降低至0.45mg·L-1,意味着97.8％的Cu(Ⅱ)从溶液中除去,通过用0.1M HCl洗涤可把Cu(Ⅱ)从吸附剂中脱离下来并且可以重复使用.