不同硅烷偶联剂对白炭黑填充天然橡胶基轮胎胶的补强效果(一)

研究了3-辛酰基硫代-1-丙基三乙氧基硅烷(NXT)、3-巯丙基-2(十三烷-1-氧-13-五(氧丙环))乙氧基硅烷(VP Si-363)和乙烯基三乙氧基硅烷(VTES)对白炭黑填充天然橡胶(NR)性能的影响,并与双-(三乙氧基甲硅烷基丙基)四硫化物(TESPT)进行了对比。硅烷用量按与TESPT乙氧基官能团同等的摩尔数增加,可改善胶料和硫化胶的性能。由于两者的乙氧基数量相等,所以使用NXT和TESPT可得到相同水平的拉伸强度。从较低的5℃tanδ和较高的60℃tanδ可以推断,以TESPT作为偶联剂的胶料若应用于轮胎胎面胶,则其湿路面抓着性和滚动阻力比NXT、VP Si-363和VTES略胜一筹。     

天然橡胶轮胎胶料中硅烷偶联剂种类对白炭黑增强效率的影响

通过与双-(三乙氧基硅烷基丙基)四硫化物(TESPT)的对比,研究了3-辛酰基硫代丙基三乙氧基硅烷(NXT)、3-巯丙基-2-[十三烷基-1-氧基-13-戊基(环氧乙烷)]乙氧基硅烷(VP Si-363)和乙烯基三乙氧基硅烷(VTES)对含白炭黑天然橡胶(NR)胶料性能的影响。结果表明,增加硅烷的用量后,至其所含乙氧基功能团与TESPT的乙氧基功能团处于相等的摩尔水平时,混炼胶和硫化胶的性能均得以提高。当NXT和TESPT中乙氧基数量相等时,胶料的拉伸强度亦相同。依据5℃时的tanδ值较小及60℃时tanδ值较大可推断,当TESPT用于胎面胶时,与以NXT、VP Si-363、VTES为偶联剂的混炼胶相比,含TESPT偶联剂的混炼胶,其抗湿路面抓着力和滚动阻力略优。     

硅丙乳液的合成及其吸水性的研究

以丙烯酸丁酯、甲基丙烯酸甲酯、丙烯酸、乙烯基三乙氧基硅烷(VTES)为原料,分别采用半连续法、种子预乳化法和后添加VTES法制得了硅丙乳液。研究了聚合工艺对硅丙乳液的吸水率、冻融稳定性、钙离子稳定性等的影响。结果表明,采用半连续法和种子预乳化法制得的硅丙乳液,冻融稳定性比较好,经过冻融循环后可以复原;采用半连续法制得的乳胶膜的吸水率随着乙烯基三乙氧基硅烷的用量的增加而降低;采用后添加VTES法制得的硅丙乳液,其吸水率则随VTES用量的增加而升高,冻融循环后发生破乳。     

聚乳酸膜辐照接枝PVP的表面性能及细胞毒性

利用γ射线辐照在聚乳酸膜表面接枝亲水性的聚N-乙烯基吡咯烷酮(PVP)来改善材料的亲水性和细胞相容性,用红外光谱(FTIR)、扫描电镜(SEM)、差示量热扫描仪(DSC)对接枝前后的聚乳酸膜进行测试,并利用接触角和吸水率分析了聚乳酸膜亲水性的变化。结果表明,接枝的PVP可以改善材料的亲水性,接枝率为16.4%的接枝共聚物吸水率较纯PLA提高了13.3倍,接触角下降了8°;细胞毒性实验结果表明,改性后的接枝共聚物无细胞毒性,并且与聚乳酸的浸提液细胞存活率101.9%相比,接枝共聚物体积分数50%和100%的浸提液的细胞存活率分别为109.3%和107.4%,表明接枝后的材料具有良好的细胞相容性,且更有利于细胞的生长。     

聚乳酸膜辐照接枝PVP的表面性能及细胞毒性研究

研究利用γ射线辐照在聚乳酸膜表面接枝亲水性的聚N-乙烯基吡咯烷酮（PVP）来改善材料的亲水性和细胞相容性,使用红外光谱(FT-IR) 、扫描电镜(SEM) 、差示量热扫描仪(DSC) 对接枝前后的聚乳酸膜进行测试,并利用接触角和吸水率分析了聚乳酸膜亲水性的变化。测试结果表明接枝的PVP可以改善材料的亲水性,接枝率为16.4%的接枝共聚物吸水率较纯PLA提高了13.3倍,接触角下降了8?;细胞毒性试验结果表明,改性后的接枝共聚物无细胞毒性,并且与聚乳酸的浸提液101.9%的细胞存活率相比,接枝共聚物50%和100%的浸提液的细胞存活率分别为109.3%和107.4%,表明接枝后的材料具有良好的细胞相容性,且更有利于细胞的生长。     

N-乙烯基吡咯烷酮-1-乙烯基咪唑共聚物的合成及应用研究

通过对单体活度、引发剂以及温度等因素的研究，确定了一套可行的N-乙烯基吡咯烷酮-1-乙烯基咪唑(VP/VI)共聚物的聚合方法。采用该方法制备的VP/VI共聚物分子量比较稳定，残留单体较低，且VP/VI共聚物具有良好的防沾色性能，应用前景和市场价值良好。     

改性纳米氮化硅/NR/SBR复合材料的制备与性能研究

采用甲基丙烯酸甲酯(MMA)-丙烯酸丁酯(BA)-乙烯基三乙氧基硅烷(VTES)三元共聚物对纳米氮化硅进行表面改性,制备改性纳米氮化硅/NR/SBR复合材料,并对复合材料的性能进行研究.结果表明,采用MMA-BA-VTES三元共聚物改性后,纳米氮化硅的平均粒径明显减小,分散性改善;当改性纳米氮化硅用量为2.5份时,复合材料的综合物理性能最优.     

原子转移自由基聚合制备两亲性聚乳酸嵌段共聚物

以双端羟基聚乳酸和2-溴丙酰溴为原料,制备了溴端基的聚乳酸;再以此作为大分子引发剂,溴化亚铜／2,2’-联吡啶为催化体系,实现了N-乙烯基吡咯烷酮的原子转移自由基聚合,制得了两亲性聚乳酸嵌段共聚物。用IR、^1H-NMR、GPC和接触角测定仪对聚合物的结构和亲水性进行了表征,并用TEM研究了聚合物在水溶液中的聚集状态。结果表明,聚乙烯基吡咯烷酮链段的引人,大大提高了聚乳酸共聚物的亲水性,且共聚物在水相中可形成一壳多核球状胶束。     

CPP/VTES/St接枝共聚物的合成与性能

以二甲苯为溶剂,过氧化苯甲酰(BPO)为引发剂,采用乙烯基三乙氧基硅烷(VTES)和苯乙烯(St)为接枝单体,自由基溶液聚合法改性氯化聚丙烯(CPP),制得接枝共聚胶黏剂。并考察了聚合单体用量及配比、溶剂用量、引发剂用量、反应温度和反应时间对树脂胶黏性能的影响。得到的最佳反应条件为：溶剂与CPP的质量比m(二甲苯)∶m(CPP)=2.5∶1,聚合原料配比m(CPP)∶m (VTES)∶m (St)∶m (BPO) =100∶2.4∶0.6∶0.2,反应温度95 ℃,反应时间3 h。在此条件下制备的共聚物粘接聚丙烯材料和钢的剪切强度分别达3.4 MPa和7.7 MPa。     

硅烷交联聚烯烃弹性体的接枝与交联

以乙烯-α烯烃共聚物(POE)接枝乙烯基硅烷制备硅烷交联弹性体,研究了POE的硅烷接枝反应、预交联和硅烷水解交联的影响因素。用红外光谱法对硅烷交联POE进行表征。用15 phr的聚丙烯与POE共混接枝乙烯基硅烷,水解制备改性弹性体,结果表明共混物具有较高的相对硅烷接枝率的同时,体系的加工流动性得到改善。当乙烯基三乙氧基硅烷(VTES)用量为5.0 phr、DCP为0.3 phr时,接枝料(T30S+DF610)具有较好的拉伸强度和断裂伸长率。     

Acrylonitrile-based copolymer membranes containing reactive groups: Surface modification by the immobilization of biomacromolecules

Asymmetric membranes fabricated from poly(acrylonitrile-co-maleic acid) (PANCMA) were immobilized with heparin and/or insulin to improve their surface properties. These biomacromolecule-immobilized PANCMA membranes were prepared by the amination of the membrane surface with ethylenediamine, followed by the reaction of the amino groups with heparin and/or insulin in the presence of 1-ethyl-3-(3-dimethyl amidopropyl) carbodiimide. The surface-modified membranes were analyzed by X-ray photoelectron spectroscopy to confirm the immobilization of the biomacromolecules. Morphological changes on the membrane surface and in the cross section were characterized by scanning electron microscopy. The surface hydrophilicity and hemocompatibility of the studied membranes were evaluated on the basis of water contact angle, platelets adhesion and cell attachment measurements. It was found that, after the immobilization of the biomacromolecules, the water contact angle and the amount of adhered platelets and macrophages on the membrane decreased significantly when compared with the nascent ones, indicating the improvement of surface hydrophilicity. Furthermore, the heparin immobilized membrane showed the best hemocompatibility among the corresponding membranes studied.     

The polydopamine-assisted heparin anchor enhances the hydrophilicity,hemocompatibility, and biocompatibility of polyurethane

Surface heparinization is an effective solution to resolve low endothelialization, poor anticoagulation, and hemocompatibility of polyurethane (PU) used as materials of small-diameter vascular grafts. Here, the effects of polydopamine (PDA) and poly (acrylic acid) (PAA) as crosslinking agents on the surface heparinization were explored. The PU membranes grafted with heparin (Hep) via dopamine (PU/PDA-Hep) showed better hydrophilicity and stability, compared to heparinized PU membranes via acrylic acid (PU/PAA-Hep). The results of X-ray photoelectron spectroscopy demonstrated that heparin was successfully grafted onto the PU surface and the grafting efficiency was high when PDA as a cross-linking agent. The grafted heparin aggregated and formed nanoparticles, and increased the surface roughness of PU membranes. The heparinized membranes demonstrated good anti-adhesion of bovine serum albumin and fibrin protein. In addition, no activated platelets or educts on heparinized PU were found by platelet adhesion tests, implying that heparin-immobilized surfaces had good hemocompatibility. Moreover, the in vitro cytocompatibility assessment showed that the PU/PDA-Hep significantly improved the proliferation of L929 cells and was superior to PU/AA-Hep. These results demonstrated that PDA-assisted surface heparinization was an effective method to improve the anticoagulant and biocompatibility of PU small-diameter vascular materials and could be extended to other implantable materials.     

两性离子改性高分子膜研究进展

两性离子因其独特的结构,能在水溶液中吸附水分子形成水合层而有效地抑制蛋白质的吸附,从而在高分子膜材料改性中得到了广泛的应用。将两性离子共混、接枝到膜表面以及化学改性膜材料,均能得到亲水性强,抗污染性和血液相容性好的高分子膜。     

Water vapor solubility of poly(lactic acid) films modified the surface by vacuum ultraviolet irradiation

Surface modification of poly(lactic acid) (PLA) film is performed via 172 nm excimer lamp irradiation. Effects on water vapor solubility and physical properties via vacuum ultraviolet (VUV) irradiation are studied systematically. After VUV irradiation, water vapor solubility increases approximately 11–43% in the low‐pressure region and approximately 20–38% in the high‐pressure region as surface hydrophilicity increased. The increase is attributed to hydrogen bonding with the carboxyl groups because of VUV radiation. The modified layer is significantly swelling after water vapor sorption. The hydrophilic layer forms a thickness of 2–3 μm from the irradiated surface via VUV radiation, but no changes are observed inside the irradiated film. Therefore, PLA film solubility after irradiation is enhanced by hydrophilicity and the swelling effect of the surface. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42200.     

Surface modification of polysulfone membranes by low‐temperature plasma–graft poly(ethylene glycol) onto polysulfone membranes

A novel and general method of modifying hydrophobic polysulfone (PSF) to produce highly hydrophilic surfaces was developed. This method is the low‐temperature plasma technique. Graft polymer‐modified surfaces were characterized with the help of Fourier transform infrared attenuated total reflection (FTIR–ATR) and X‐ray photoelectron spectroscopy (XPS). Study results demonstrated that poly(ethylene glycol) (PEG) could be grafted onto the PSF membrane surface by low‐temperature plasma. The hydrophilic character of the modified surfaces was increased in comparison with that of the parent membrane. The contact angle for a modified PSF membrane was reduced apparently. We analyzed the effectiveness of this approach as a function of plasma operating variables including plasma treatment power and treatment time. Hence, plasma‐induced graft polymer modification of membranes can be used to adjust membrane performance by simultaneously controlling the surface hydrophilicity and hemocompatibility. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 979–985, 2000     

Ultrasonication‐Induced Modification of Hydroxyapatite Nanoparticles onto a 3D Porous Poly(lactic acid) Scaffold with Improved Mechanical Properties and Biocompatibility

A 3D porous poly(lactic acid) (PLA) scaffold with high porosity and well‐connected pores is fabricated using a vacuum‐assisted solvent casting technique. Its surface is modified with hydroxyapatite (HA) nanoparticles using ultrasonication to prepare an HA‐modified PLA/HA scaffold. For reference, an HA‐blended (b‐PLA‐HA) scaffold is fabricated via the solution blending method. The morphology, porosity, hydrophilicity, swelling ratio, mechanical properties, and cell viability of the PLA, b‐PLA‐HA, and PLA/HA scaffolds are systematically studied. The results show that HA nanoparticles are successfully introduced onto the surface of the PLA/HA scaffold, and strong interactions occur between the HA nanoparticles and the PLA matrix. The PLA/HA scaffold still has a high porosity of more than 85% after ultrasonication. The hydrophilicity and mechanical properties of the PLA/HA scaffold are significantly higher than those of the PLA and b‐PLA‐HA scaffolds. Compared with the PLA and b‐PLA‐HA scaffolds, the attachment and growth of mouse embryonic osteoblasts cells (MC3T3‐E1) cultured on the PLA/HA scaffold significantly improve, due to most HA nanoparticles on the surface, resulting in a good and direct interaction between the cells and the scaffold. Therefore, the PLA/HA scaffold possesses great potential to be used as a tissue engineering scaffold.     

Appraisal of ε-Caprolactam and Trimellitic Anhydride Potential as Novel Chain Extenders for Poly(lactic acid)

The potential of ε-caprolactam (CAP) and trimellitic anhydride (TMA) compounds as novel chain extenders for poly(lactic acid) (PLA) has been assessed; the amounts of 0.01, 0.025, and 0.05 wt% each additive have been added. The chain extension was evidenced by the increase in PLA/CAP and PLA/TMA viscosities in mixing torque measurements and by infrared spectroscopy. PLA reaction with CAP and TMA has also been confirmed from contact angle and surface free energy studies, which have shown that the increase in TMA amount decreased the hydrophilicity of PLA due to the decreased concentration of terminal surface hydroxyl groups. However, the addition of CAP accentuated the PLA hydrophilicity as indicated by the increase in the polar component of the surface energy. On the other hand, the glass transition temperature of PLA/TMA and PLA/CAP decreased as a result of a local plasticizing effect, which favored the chain mobility and the crystallization of PLA due to the concomitant nucleating effect of the chain extenders moieties too. Furthermore, the higher molecular weight of PLA/CAP and PLA/TMA was responsible for their increased thermal stability and higher impact strength with respect to PLA. POLYM. ENG. SCI., 60:944–955, 2020. © 2020 Society of Plastics Engineers     

聚丙烯膜表面磷脂自组装/交联改性及其表面性能

发展了一种基于分子自组装/交联的聚丙烯微孔膜(PPMM)表面改性方法,以含不饱和长烷基链的两亲性天然卵磷脂为改性剂,首先通过分子自组装在PPMM表面形成类磷脂组装层,再采用紫外线原位聚合交联方法在PPMM表面构建稳定的类磷脂仿生修饰层,进而赋予PPMM表面优异的亲水性和生物相容性。分别采用FTIR/ATR和XPS分析确证了改性前后膜表面基团及化学成分的变化。通过水接触角测定、荧光标记蛋白质吸附和酶联免疫吸附(ELISA)实验,考察了类磷脂仿生修饰前后膜表面亲水性和抗蛋白质吸附性能,发现类磷脂仿生修饰后PPMM表面水接触角由130°下降至30°,抗蛋白质吸附性能也得到明显改善;自组装/交联改性PPMM经多次水洗后仍能保持良好的亲水性和抗蛋白质吸附性能,表明膜表面所形成的类磷脂仿生修饰层具有良好的稳定性。     

可溶性鸡蛋壳膜蛋白在聚乙烯表面固定的研究

采用等离子体预处理的技术，将具有良好生物相容性的可溶性鸡蛋壳膜蛋白(SEP)固定在聚合物PE膜表面，通过接触角测定、全反射衰减式傅立叶红外光谱(ATR—FTIR)和光电子能谱(XPS)证明固定方法的可靠性，并进一步通过纳米二氧化硅辅助的方法提高了可溶性鸡蛋壳膜蛋白在聚合物表面的固定量。同时，采用SEP的良溶剂对SEP固定后的PE膜表面进行长时间洗涤的结果表明，SEP均可以被牢固地固定在PE膜的表面，完全可以耐受在使用过程中生体组织液的侵蚀，且SEP表面的良好亲水性也将使之更有利于促进生体组织细胞的成长和繁殖。     

聚乳酸表面羧基化改性及细胞相容性研究

采用紫外活化二氧化氯自由基（ClO₂·）氧化甲基的方法,在聚乳酸（PLA）表面接枝了羧基等含氧官能团,以增加PLA表面的亲水性和生物相容性。通过X射线光电子能谱分析和接触角分析,探究了改性后PLA表面元素组成的变化、最佳的氧化条件及氧化反应对PLA表面亲水性的影响。通过拉伸实验分析了氧化过程对PLA力学性能的影响。通过体外细胞增殖和细胞活性测试研究了改性后PLA表面的生物相容性变化。结果表明,羧基等含氧官能团在PLA表面成功生成;最佳氧化时间为10 min ,最佳氧化温度为90 ℃,该条件下氧化后材料的表面接触角由82 °降低至62.5 °,表面亲水性得到改善;改性后PLA的拉伸强度不变,断裂伸长率略有下降;氧化后PLA表面显示出更好的细胞黏附能力和细胞增殖能力,更有利于细胞的生长。