改性高岭土/水性聚氨酯复合材料的制备与表征

采用钛酸酯偶联剂干法改性高岭土,配成母液,用此母液乳化中和后的聚氨酯预聚体,制得改性高岭土/水性聚氨酯复合材料(WPUM)。研究了复合材料的乳液粒径、胶膜力学性能、结晶性和热稳定性等性能。结果表明:复合材料乳液粒径随着改性高岭土质量分数的增加,先增加后减小;改性高岭土的加入可以明显提高水性聚氨酯胶膜的力学性能,当改性高岭土质量分数为1.6%时,复合材料的断裂伸长率与纯聚氨酯胶膜相比提高了13%;X射线衍射法(XRD)分析结果显示,改性高岭土促进了聚氨酯的微相分离;热重分析法(TG)、差示热重法(DTG)分析结果表明,水性聚氨酯复合材料胶膜热分解的起始温度无变化,硬段最高热失重温度略有降低。     

2种酸改性高岭土的制备及表征

为了研究酸改性高岭土的结构变化,分别选择用不同浓度的浓硫酸和浓盐酸对鄂尔多斯高岭土进行了酸改性,制得了酸改性高岭土样品,并用IR、SEM、EDS等表征手段对所制的样品进行分析。2种酸改性后均可使高岭土的孔道结构更紧密,硫酸改性比盐酸改性更有利于高岭土中铝的浸出。     

纳米银/巯基化淀粉复合材料的制备与表征

巯基乙酸与直链淀粉发生酯化反应,制备巯基化淀粉。微波辐射法制备纳米银/巯基化淀粉的复合材料。通过红外光谱、X射线衍射仪、扫描电镜、紫外光谱对复合材料进行表征。结果表明,巯基乙酸成功改性淀粉,在不加还原剂的前提下,微波辐射制备出淀粉/纳米银核壳结构的复合材料。     

Preparation and characterization of starch/polycaprolactone blend

To make starch/polycaprolactone (PCL) blend with high miscibility, starch was chlorinated (starch‐Cl) by using methanesulfonylchloride (CH₃SO₂Cl) in dimethylformamide (DMF) prior to blending. Starch‐Cl/PCL blends were prepared by the mixing between starch‐Cl and PCL solutions under various conditions. To study the change of structure, thermal and physical characteristics of starch‐Cl/PCL blend, FTIR, DSC, SEM, and solvent resistance were measured. By blending starch‐Cl and PCL, a chemical reaction occurred partially in blend (FTIR result); thereby, the miscibility (DSC and SEM results) and solvent resistance were increased. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1716–1723, 2004     

亲水改性高岭土/聚氨酯乳液的制备及性能表征

钛酸酯偶联剂对水洗高岭土进行亲水改性,通过机械共混法制备了亲水改性高岭土/水性聚氨酯复合材料,研究了复合材料的力学性能、耐热性能。结果表明,当改性高岭土质量分数2.0%时,复合材料的拉伸强度为24.4 MPa,比聚氨酯增加53.1%,断裂伸长率达492%,增加9.6%,实现了复合材料的增韧增强,同时热稳定性也有所提高。     

聚丙烯酸/高岭土复合高吸水树脂的制备及结构性能研究

以丙烯酸和高岭土为原料,采用水溶液聚合法制备了聚丙烯酸/高岭土复合高吸水树脂,对其结构性能进行了研究。结果表明:当丙烯酸质量分数为20%,高岭土质量分数为10%,过硫酸钾质量分数为0.13%,N,N'-亚甲基双丙烯酰胺质量分数为0.2%,反应温度为80℃,反应时间为3 h时,所制的聚丙烯酸/高岭土复合高吸水树脂表面形貌良好,高岭土分散均匀,吸水倍率为132 g/g,保水率为93.9%,凝胶形变量为2.3 mm;聚丙烯酸高吸水树脂的吸水倍率为121 g/g,保水率为82.5%,凝胶形变量为7.1 mm;高岭土的加入不仅提高了聚丙烯酸树脂的吸水倍率、吸水速率与保水率,且显著提高了聚丙烯酸树脂的凝胶强度。     

硫酸改性高岭土的制备及表征

为了对比高岭土改性前后的结构变化,将鄂尔多斯高岭土分别用10%、20%、30%、40%、50%的硫酸进行改性,得到酸改性高岭土样品。采用IR、XRD、SEM、BET、EDS等对样品进行表征分析。结果表明,由于硫酸的吸水性,随着酸浓度的增加,脱除高岭土中吸附水的能力越强;酸改性浓度的变化对高岭土的结构影响不大;改性后的高岭土比表面积减小,表面粗糙度增加,密集堆积,凝结成块状,有堆积孔道出现;硫酸改性会使高岭土中大量的铝被浸出。     

羧化淀粉/PVA复合水凝胶的制备与性质研究

由顺丁烯二酸酐羧化的淀粉与聚乙烯醇按比例进行溶液混合,经冷冻-解冻形成物理交联复合水凝胶。采用WAXD和DSC分析了复合凝胶的结晶性和热性能,探讨了羧化淀粉的含量及其取代度对凝胶结构和溶胀性质的影响。结果表明,羧化改性增强了淀粉与PVA的相互作用,复合水凝胶的稳定性和溶胀性取决于羧化淀粉的质量分数及其取代度。     

Preparation and characterization of polyurethane foam/activated carbon composite adsorbents

A polyurethane foam (PU)/activated carbon (AC) composite was prepared by adding granular AC during the synthesis of PU foam, and subsequent carbonization. Nitrogen adsorption?Cdesorption isotherms and scanning electron microscopy were used to ascertain the pore structure and surface morphology of the samples. The prepared composite foams possess well-developed open cell structures. Under the conditions investigated, a higher carbonization temperature promoted development of porous structures. Thermogravimetric and derivative thermogravimetric analyses revealed the thermostability of the PU foam precursor/AC composites. The adsorption performance of the composites was evaluated using phenol, iodine and methylene blue (MB) as model compounds. A PU foam/AC composite with a maximum specific surface area of 655.0?m²/g, maximum iodine number of 525.2?mg/g, and maximum adsorption capacity of MB and phenol of 100 and 66.5?mg/g, respectively, was achieved.     

凹凸棒/淀粉接枝AM-AMPS纳米复合吸水材料的制备及表征

在反应温度为30℃,引发剂质量分数为0.02%,交联剂质量分数为0.02%,反应时间为10 min的条件下,原位插层聚合制备了凹凸棒/淀粉接枝AM-AMPS纳米复合材料。通过正交实验研究了复合材料在蒸馏水和质量分数为2%盐水中的吸水倍率的优化工艺条件。通过红外光谱研究发现,复合材料形成了致密的柱状网络结构,凹凸棒与高分子基体有较多粘连。X射线衍射(XRD)结果发现,复合材料中凹凸棒片层(001)面的层间距增大到2.13 nm,形成了剥离型纳米插层复合吸水材料。     

Preparation and characterization of amphiphilic starch nanocrystals

In this article, amphiphilic starch nanocrystals were synthesized by graft copolymerization of starch nanocrystals with styrene in aqueous emulsion system. The starch nanocrystals of size around 50 nm were used, which were prepared by acid hydrolysis of corn starch. The structure of starch‐g‐polystyrene nanocrystals was characterized by Fourier transform infrared and ¹H nuclear magnetic resonance (¹H NMR). The crystalline structure as well as its particle morphology was studied by X‐ray diffraction and scanning electron microscopy, respectively. The results indicated that the amphiphilic starch nanocrystals obtained exhibit the size around 80–100 nm. Its crystalline structure is basically not changed after grafting polystyrene suggested that the polystyrene was essentially grafted on the surface of starch nanocrystals. Wettability experiments indicated that the prepared starch‐g‐polystyrene nanocrystals can be uniformly dispersed both in water phase and oil phase revealing excellent amphiphilicity. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation and characterization of colloidal carbon sphere/rigid polyurethane foam composites

Sucrose decomposed under hydrothermal conditions, generating colloidal carbon spheres (CCSs) with a perfectly spherical morphology. X‐ray diffraction indicated that the main component of the CCSs was disordered carbon, and massive hydroxyl groups existed on the surface, as confirmed by Fourier transform infrared spectroscopy. CCSs were first introduced into polyurethane foams (PUFs), and CCS‐reinforced PUF (PUF/CCS) composites were synthesized. The introduction of CCSs did not increase the viscosity of polyol/CCS blends significantly. The good dispersion of CCSs and the compatibility between CCSs and polyurethane were confirmed by transmission electron microscopy measurements. The results of mechanical testing showed that PUF/CCS composites exhibited greatly improved mechanical properties in comparison with neat PUFs, and this could be ascribed to the finer cell structure of the PUF/CCS composites, which was inspected with scanning electron microscopy. Thermogravimetric analysis indicated that the effects of CCSs on the thermal stability of the foams were slight. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

木磺基聚氨酯泡沫塑料的制备和性能表征

研究了木磺基聚氨酯泡沫塑料的制备、热稳定性能、压缩性能及对其进行显微结构分析。通过热重失重率（TG）和失重速率（DTG）曲线得木磺基聚氨酯泡沫塑料起始分解温度和峰值分解温度分别为220℃和360℃。结果表明,木质素磺酸盐使材料热稳定性有较大改善,保温性能较好。通过压缩试验,木磺基聚氨酯,泡沫塑料的10％压缩强度σ10为544kPa。结果表明,木质素磺酸盐对提高材料的压缩性能的贡献大。通过对加载后木磺基聚氨酯泡沫塑料进行扫描电镜分析,探讨增强机理。     

双负载抗生素亲水性聚氨酯泡沫的制备与表征

因细菌、异物和炎症等因素引起的慢性伤口会有过量的伤口渗出液流出,影响伤口周围健康皮肤,不利于伤口愈合.针对以上问题,我们开发了双负载亲、疏水性抗生素的亲水性聚氨酯泡沫作为慢性伤口的创面敷料.通过电子显微镜观察,泡沫的孔径均匀地分布在200～400 μm之间.聚氨酯泡沫中载入的药物对聚氨酯泡沫的力学性能略有影响,对吸液率...     

改性淀粉/PVA生物降解塑料膜的制备及表征

以氧化改性过后的马铃薯淀粉为原料,经过交联、增塑、增强后,采用流延的方法制备生物降解塑料膜,研究了改性淀粉、丙三醇、甲醛、尿素、聚乙烯醇、反应温度等因素对模力学性能的影响。结果表明,影响膜强度主要因素为丙三醇的含量,其次为甲醛、改性淀粉、尿素的量、反应时间及聚乙烯醇的量。最佳条件为:水100 mL,改性淀粉3.3 g,尿素1.0 g,聚乙烯醇1.2 g,甲醛1.6 mL,丙三醇0.6 mL,反应时间110 min。在此条件下,制得膜的拉伸强度为20.05 MPa,断裂伸长率为65%。     

丙烯酰胺改性玉米淀粉/PVA复合膜的制备与表征

为了改善聚乙烯醇（PVA）膜的机械性能,选用玉米淀粉为原材料,50℃条件下以过硫酸铵和尿素为引发剂,同时加入丙烯酰胺对淀粉进行接枝改性,制备得到丙烯酰胺改性的玉米淀粉/PVA复合膜。其中,优化改性淀粉的接枝率确定最佳合成条件为淀粉/丙烯酰胺的质量比为3∶7、引发剂过硫酸铵占单体总质量的0.5%、尿素占单体总质量的0.5%。进一步利用优化的改性淀粉为改性剂,制备了系列改性玉米淀粉/PVA复合膜。采用傅里叶红外光谱、扫描电子显微镜（SEM）对复合膜的组成与结构进行表征,同时测定复合膜的机械性能、耐水性、耐热性等物化特性,结果表明30%ST-0.50%APSU改性淀粉的单体转化率为95.0%,接枝率为85.2%。 30%ST-0.50%APSU/PVA复合膜的耐热性能轻微下降,但断裂伸长率提高了256%,耐水性能提高了43.1%。     

天然雌激素色谱-质谱检测方法研究进展

天然雌激素在生物体中起着重要的作用,各种样品中天然雌激素的检测具有一定的难度,液-液萃取、固相萃取及固相微萃取等样品前处理方法结合气相色谱-质谱及液相色谱-质谱检测成为天然雌激素检测的重要手段,综述了天然雌激素的检测方法研究进展情况。     

改性淀粉木材胶粘剂的制备及表征

以过硫酸铵为引发剂,以玉米淀粉、乙酸乙烯酯和丙烯酸丁酯为原料,制备改性淀粉木材胶粘剂,在单因素实验的基础上,进行L_(16)(4~5)正交实验,优化改性淀粉木材胶黏剂的制备条件。结果表明,最佳制备工艺参数为:引发剂浓度11 mmol/L,单体与淀粉质量比为1.0,反应温度70℃,单体乙酸乙烯酯和丙烯酸丁酯的质量比为3∶2,反应时间3 h。在此条件下,接枝率达91.3%,制备的改性淀粉木材胶粘剂性质较佳,各项指标均达到聚乙酸乙烯酯木材胶粘剂化工行业标准HG/T 2727—2010。     

Preparation and characterization of electromagnetic interference shielding polyimide foam

This article focused on the preparation and characterization of ultralight and high‐temperature resistant polyimide foam (PIF) for electromagnetic interference shielding. PIF was first prepared based on a one‐pot process by the primary reactions of derivatives of pyromellitic dianhydride and polyaryl polymethylene isocyanate. Then, PIFs with silver (0) coating were then prepared by spraying silver (0) on the surfaces of PIF through physical spraying method. The surface density of silver coating was 0.18 kg/m², and the densities of silver‐coated PIFs were less than 23 kg/m³. The scanning electron microscopy coupled with an energy‐dispersive X‐ray spectrometer (EDX) measurement were carried out to investigate the morphological and chemical properties of uncoated and coated PIFs. For coated PIFs, the EDX spectrums indicated increasing higher silver proportions from interior to exterior surface, together with increasing higher carbon proportions from exterior surface to interior. Thermogravimetry/Fourier transform infrared instrument that combined thermogravimetric analysis with pyrolysis product analysis by Fourier transform infrared spectroscopy were applied to investigate the thermal stability and pyrolysis products of uncoated and coated PIFs. The results indicated that the thermal properties of silver‐coated PIFs were improved obviously with the 5% weight loss temperature higher than 400°C and the residual weight retentions at 800°C ～ 80%. In the frequency range 200–7000 MHz, the EMI shielding efficiency with one surface and two surfaces coated with silver were in the range of 36.4–60.7 dB and 61.6–95.6 dB, respectively. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013