Electrospun poly(L‐lactide)/poly(ε‐caprolactone) blend fibers and their cellular response to adipose‐derived stem cells

Polymer blending is one of the most effective methods for providing new, desirable biocomposites for tissue‐engineering applications. In this study, electrospun poly(L ‐lactide)/poly(ε‐caprolactone) (PLLA/PCL) blend fibrous membranes with defect‐free morphology and uniform diameter were optimally prepared by a 1 : 1 ratio of PLLA/PCL blend under a solution concentration of 10 wt %, an applied voltage of 20 kV, and a tip‐to‐collector distance of 15 cm. The fibrous membranes also showed a porous structure and high ductility. Because of the rapid solidification of polymer solution during electrospinning, the crystallinity of electrospun PLLA/PCL blend fibers was much lower than that of the PLLA/PCL blend cast film. To obtain an initial understanding of biocompatibility, adipose‐derived stem cells (ADSCs) were used as seed cells to assess the cellular response, including morphology, proliferation, viability, attachment, and multilineage differentiation on the PLLA/PCL blend fibrous scaffold. Because of the good biocompatibility and nontoxic effect on ADSCs, the PLLA/PCL blend electrospun fibrous membrane provided a high‐performance scaffold for feasible application in tissue engineering using ADSCs. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

TDI三聚体的合成工艺研究

以自制的Mannich碱催化剂C-0116合成甲苯二异氰酸酯(TDI)三聚体聚氨酯固化剂,研究了合成工艺条件。在氮气保护下,向TDI和乙酸丁酯混合溶液中滴加Mannich碱催化剂,控制温度、时间、用量等条件,最终得到TDI三聚体。实验结果表明:该催化剂催化活性高,在40℃下,以滴加方式催化反应,8 h可达到反应终点,—NCO含量在7%以上,由气相色谱测定得到的三聚体中游离单体含量低至0.7%;实验中添加适量的十二醇进行改性处理,大大改善了三聚体的二甲苯容忍度。     

Tensile deformation mechanisms of polypropylene/elastomer blends reinforced with short glass fiber

Polypropylene hybrid composites reinforced with short glass fiber (SGF) and toughened with styrene–ethylene butylenes–styrene (SEBS) elastomer were prepared using extrusion and injection‐molding techniques. Moreover, hybrids compatibilized with SEBS‐grafted maleic anhydride (SEBS‐g‐MA) and hybrid compatibilized with PP grafted with maleic anhydride (PP‐g‐MA) were also fabricated. The matrix of the latter hybrid was designated as mPP and consisted of 95% PP and 5% PP‐g‐MA. Tensile dilatometry was carried out to characterize the fracture mechanisms of hybrid composites. Dilatometric responses showed that the elastic deformation was the dominant deformation mechanism for the SGF/SEBS/PP and SGF/SEBS‐g‐MA/PP hybrids. However, cavitation deformation prevailed over shearing deformation for both hybrids at the higher strain regime. The cavitation strain resulted from the debonding of glass fibers and from the crazing of the matrix in the SGF/SEBS/PP hybrid. In contrast, the cavitation was caused by the debonding of SEBS particles from the matrix of the SGF/SEBS‐g‐MA/PP hybrid. The use of PP‐g‐MA resulting in elastic deformation was the main mode of deformation in the low‐strain region for the SGF/SEBS/mPP and SEBS/SEBS‐g‐MA/mPP hybrids; thereafter, shearing appeared to dominate at the higher strain regime. This was attributed to the MA functional group improving the bonding between the SGF and PP. The correlation between fracture morphology and dilatometric responses also is presented in the article. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 441–451, 2003     

乙二醛在纳米TiO2-Pt电极上的电催化氧化

通过电沉积修饰铂微粒制备Ti基纳米TiO₂-Pt（Ti/nano-TiO₂-Pt）修饰电极,采用循环伏安法研究了乙二醛在Ti/nano-TiO₂-Pt上的电催化氧化。结果表明：Ti/nano-TiO₂-Pt修饰电极对乙二醛的氧化呈现较高的电催化活性,可作为乙二醛电氧化合成乙醛酸的高活性催化电极。     

丙烯酸和苯乙烯改性PP/PS结晶与熔融行为

制备了苯乙烯（St）、St与丙烯酸（AA）混合物、丙烯酸接枝聚丙烯（PP-g-AA）改性聚丙烯／聚苯乙烯（PP／PS）共混物以及AA，St改性PP（原位形成PP／PS共混物）。用差示扫描量热仪（DSC）研究了3种改性方法对共混物中PP结晶与熔融行为的影响。结果表明，PS对PP的结晶与熔融温度影响不大，PP-g-AA则提高共混物中PP的结晶温度。St以及St与AA混合单体对PP／PS中PP结晶温度影响不大，但AA改性提高PP／PS中PP结晶温度。St加入PP导致PP结晶温度下降，St与AA混合单体原位聚合则提高PP的结晶温度。改性对共混物中PP的熔融温度影响不大，但是熔融峰形与结晶温度高低有关。红外光谱证实St与AA混合单体改性PP中有PP-g-AA形成，但改性共混物中没有PP-g-AA形成。     

碘量法测定铜铬混合粉中的铜

试样用王水溶解,在氨性溶液中实现铜铬的分离。实验表明,加氨水可以消除铬的干扰,从而确定了碘量法快速测定铜铬混合粉中铜的分析方法。     

混凝土芯水泥土组合桩复合地基沉降规律研究

对采用混凝土芯水泥土组合桩进行地基处理的建筑工程进行了长期、系统的沉降观测和统计分析。观测和分析结果表明:施工阶段,在正常的施工进度下,建筑物的平均沉降值与基底压力(或施工层数)成近似线性关系变化;在封顶后约18个月内,沉降随时间增长较快;封顶36个月后,沉降趋于稳定。沉降计算值与实测值比较结果表明,可参照CFG桩的沉降计算方法估算混凝土芯水泥土组合桩复合地基最终沉降量。     

基于FFT方法对微小信号3D分析研究

为了全面准确地分析微小信号,引入基于FFT技术的三维方法,利用LabVIEW2011高级开发者工具包编程设计,实现将微小信号从一维显示转换成三维能量谱的形式。使用所设计的程序成功实现对微小信号的准确分析。采用该方法可以实现对于微小信号的全面研究。     

超高分子量聚乙烯纤维表面紫外接枝聚合改性研究

以二苯甲酮(BP)为引发剂,采用新型二步紫外接枝法在超高分子量聚乙烯(UHMWPE)纤维表面接枝了丙烯酸(AA)、甲基丙烯酸(MAA)等活性单体,利用全反射傅里叶变换红外光谱(ATR-IR)、电子显微镜(SEM)分析证明了接枝层的存在,此外还通过紫外吸收光谱(UV)、全反射傅里叶变换红外光谱(ATR-IR)、热裂解色谱质谱分析(Py-GCMS)对反应机理进行了分析.探索了接枝条件对接枝率的影响,接枝改性后的超高分子量聚乙烯纤维的粘结性能和亲水性能大大提升,其中界面剪切强度提升160.9％,水接触角从112.0°下降为67.88°.     

生物降解PBAT的合成与表征

为利用废弃PET制备生物降解的脂肪-芳香族共聚酯材料,研究了废弃PET在1,4-丁二醇存在下醇解制备聚对苯二甲酸丁二醇酯低聚物(BHBT),己二酸与丁二醇反应制备聚己二酸丁二醇酯(PBA)的条件,BHBT和PBA缩聚成脂肪-芳香族共聚酯(PBAT)的影响因素,结果表明,采用废弃PET成功制备了有良好的生物降解性能的脂肪-芳香族共聚酯PBAT.