Dynamic and buckling analysis of polymer hybrid composite beam with variable thickness

This work deals with a study of the dynamic and buckling analysis of polymer hybrid composite(PHC) beam. The beam has variable thickness and is reinforced by carbon nanotubes(CNTs) and nanoclay(NC) simultaneously. The governing equations are derived based on the first shear deformation theory(FSDT). A three-phase HalpinTsai approach is used to predict the mechanical properties of the PHC. We focus our attention on the effect of the simultaneous addition of NC and CNT on the vibration and buckling analysis of the PHC beam with variable thickness. Also a comparison study is done on the sensation of three impressive parameters including CNT, NC weight fractions, and the shape factor of fillers on the mechanical properties of PHC beams,as well as fundamental frequencies of free vibrations and critical buckling load. The results show that the increase of shape factor value, NC, and CNT weight fractions leads to considerable reinforcement in mechanical properties as well as increase of the dimensionless fundamental frequency and buckling load. The variation of CNT weight fraction on elastic modulus is more sensitive rather than shear modulus but the effect of NC weight fraction on elastic and shear moduli is fairly the same. The shape factor values more than the medium level do not affect the mechanical properties.

Oral delivery of superoxide dismutase by lipid polymer hybrid nanoparticles for the treatment of ulcerative colitis

Protein-based drugs have received extensive attention in the field of drug research in recent years.However,protein-based drug activity is difficult to maintain during oral delivery,which limits its application.This study developed bifunctional oral lipid polymer hybrid nanoparticles(R8-PEG-PPNPs)that deliver superoxide dismutase(SOD)for the treatment of ulcerative colitis(UC).R8-PEG-PPNPs was composed of PCADK,PLGA,lecithin,and co-modified with stearic acid-octa-arginine and polyethylene glycol.The nanoparticles(NPs)are uniformly dispersed with a complete spherical structure.In vitro stability and release studies showed that R8-PEG-PPNPs exhibited good stability and protection.In vitro cell culture experiments demonstrated that R8-PEG-PPNPs as carriers have no significant toxic effects on cells at concentration below 1000µg/mL and promote cellular uptake.In experiments with ulcerative colitis mice,R8-PEG-PPNPs were able to enhance drug absorption by intestinal epithelial cells and accumulate effectively at the site of inflammation.Its therapeutic effect further demonstrates that R8-PEG-PPNPs are a promising delivery system for oral delivery of protein-based drugs.

Functional micro‐concrete 3D hybrid structures f abricated by two‐photon polymerization

Arbitrary micro-scale three-dimensional(3D)structures fabrication is a dream to achieve many exciting goals that have been pursued for a long time.Among all these applications,the direct 3D printing to fabricate human organs and integrated photonic circuits are extraordinary attractive as they can promote the current technology to a new level.Among all the 3D printing methods available,two-photon polymerization(2PP)is very competitive as it is the unique method to achieve sub-micron resolution to make any desired tiny structures.For the conventional 2PP,the building block is the photoresist.However,the requirement for the building block is different for different purposes.It is very necessary to investigate and improve the photoresist properties according to different requirements.In this paper,we presented one hybrid method to modify the mechanical strength and light trapping efficiency of the photoresist,which transfers the photoresist into the micro-concretes.The micro-concrete structure can achieve±22%strength modification via a silica nano-particles doping.The structures doped with gold nano-particles show tunable plasmonic absorption.Dye doped hybrid structure shows great potential to fabricate 3D micro-chip laser.

Analysis on the Durability of Hybrid Polymer Composites for Power FGD System

The corrosion condition of flue gas desulfurization (FGD) equipment for the coal-fired power plant was defined as the strong corrosion grade. The lining system of hybrid polymer composite was used in internal cylinder of steel chimney, and a corrosion-resistant and heat-resistant protective layer was formed on the metal surface. The corrosion-resistant and ageing-resistant properties of hybrid polymer composite prepared at low temperature after four years of practical use were investigated by differential scanning calorimeter (DSC), scanning electron microscopy (SEM) and measurement of gravimetric variation, contact angle, abrasion resistance, bonding strength and tensile strength. The properties of hybrid polymer composites prepared at 25℃ and –15℃ were comparatively analyzed in the paper.

Preparation and properties of a POSS-containing organic-inorganic hybrid crosslinked polymer

A novel POSS-containing organic-inorganic hybrid crosslinked polymer was prepared by hydrosilylation reaction of octahydridosilsesquioxane （TsHs） with 4,4＇-bis（4-altyloxybenzoyloxy）phenyl （diene A）. Its structure and property was characterized by FFIR, 29Si NMR, TGA and ellipsometer, respectively. The results show that the hybrid polymer possesses high thermal stability and low dielectric constant of 1.97 at optical frequencies.

Evaluation of Cisplatin-Loaded Polymeric Micelles and Hybrid Nanoparticles Containing Poly(Ethylene Oxide)-Block-Poly(Methacrylic Acid) on Tumor Delivery

Particulate carriers such as polymeric micelles (PMs) and liposomes have been investigated to increase drug accumulation in tumors and reduce distribution to healthy tissues. In this study, we prepared PM and hybrid nanoparticles (HNPs) with poly(ethylene oxide)-block-poly(methacrylic acid) (PEO-b-PMAA) for loading cisplatin, and evaluated cisplatin release, cytotoxicity, and biodistribution in mice. PM composed of PEO-b-PMAA and HNPs composed of egg phosphatidylcholine (EPC)/PEO-b-PMAA at molar ratios of 50/2.8 (HNP-P5) and 50/50 (HNP-P50), respectively, were prepared by a nanoprecipitation method. The sizes of PM, HNP-P5, and HNP-P50 after inclusion of cisplatin were approximately 200, 100, and 55 nm, respectively, and their entrapment efficiencies were approximately 44% - 66%. In the drug-release study, HNP-P5 and HNP-P50 showed reduced release of cisplatin compared with PM. Regarding the cytotoxic assay, HNP-P5 exhibited lower cytotoxicity for mouse Lewis lung carcinoma (LLC) and mouse colon carcinoma Colon 26 cells than PM and HNP-P50. In terms of biodistribution, PM could significantly improve blood circulation and tumor accumulation after intravenous injection into Colon 26 tumor-bearing mice compared with free cisplatin, but HNP-P5 and HNP-P50 did not. EPC in HNPs might be destabilized in the circulation, although it could reduce release of cisplatin in in vitro experiments. This study suggested that polymeric micelles composed of PEO-b-PMAA are a better carrier for cisplatin than hybrid nanoparticles composed of PEO-b-PMAA and EPC.

SYNTHESIS AND CHARACTERIZATION OF STRUCTURALLY WELL-DEFINED POLYMER-INORGANIC HYBRID NANOPARTICLES VIA ATRP

Atom transfer radical polymerization (ATRP) using cuprous chloride/2,2'-bipyridine (bipy) was applied to graft polymerization of styrene on the surface of silica nanoparticles to synthesize polymer-inorganic hybrid nanoparticles, 2-(4Chloromethylphenyl) ethyltriethoxysilane (CTES) was immobilized on the surface of silica nanoparticles through condensation reaction of the silanol groups on silica with triethoxysilane group of CTES. Then ATRP of St was initiated by this surface-modified silica nanoparticles bearing benzyl chloride groups, and formed PSt graft chains on the surface of silica nanoparticles. The thickness of the graft chains increased with reaction time. End group analysis confirmed the occurrence of ATRP. Thermal analysis indicated that thermal stabilization of these resulting hybrid nanoparticles also increases with polymerization conversion. The results above show that this 'grafting from' reaction could be used for the preparation of polymer-inorganic hybrid nanoparticles with controlled structure of the polymer's end groups.

PAC-P(AM-BA)杂化高分子絮凝剂制备及絮凝效能评价

针对油田化学驱污水难处理问题,采用水溶液自由基胶束聚合法,以聚合氯化铝(PAC)为无机组分,丙烯酰胺(AM)、丙烯酸丁酯(BA)为有机单体,合成一种新型无机-有机杂化高分子絮凝剂(PAC-P(AM-BA))。利用傅里叶变换红外光谱仪(FT-IR)、热重分析仪(TGA)、扫描电子显微镜(SEM)和比表面积分析仪(BET)对絮凝剂进行表征。结果表明,BA以化学键连接在聚丙烯酰胺(PAM)长链中,无机组分与有机组分之间以离子键连接。PAC-P(AM-BA)热分解温度为233.93℃,比表面积为30.351m^(2)·g^(-1)。絮凝实验结果表明,PAC-P(AM-BA)最佳投加量为20 mg·L^(-1),沉降时间为10 h,其絮体分形维数为1.733。在絮凝效能对比实验中,PAC-P(AM-BA)的平均除油率为90.3%,较阳离子聚丙烯酰胺(CPAM)和复配型絮凝剂(PAC+PAM)分别高出16.4%和29.0%。

Synthesis and Characterization of Poly(St-co-BA) Latex with an Organic-Inorganic Hybrid Compound as Emulsifier

A poly (St-co-BA) latex was successfully synthesized by using an organic-inorganic hybrid compound (OIHC), an aliphatic carboxylate sodium/nano-silica composite, as the emulsifier, and investigated by particle size analyzer, transmission electron microscope (TEM), optical contact angle measurement (OCA) and dynamic mechanical analyzer (DMA). It was found that the protective agent, sodium polyacrylate (PA),could obviously improve the polymerization stability and the functional monomer, glycidyl methacrylate (GMA), could enhance the store stability of the latex. The particle size of poly(St-co-BA) latex decreased and then leveled off as OIHC content increased. TEM shows that the prepared polymers were a~:tually organic-inorganic nanocomposites, and these films have better waterproof property than those prepared by traditional poly(St-co-BA) latex or organic silicone modified poly(St-co-BA) latex. The nanocomposite polymer has much higher glass transition temperature than organic silicone modified poly(St-co-BA) polymer containing the same organic silicone content.

SYNTHESIS OF HYBRID MESOPOROUS POLYSTYRENE-SILICA MATERIALS WITH NON-SURFACTANT CITRIC ACID AS TEMPLATE VIA SOL-GEL PROCESS

Hybrid mesoporous polystyrene-silica materials were successfully prepared through HCl-catalyzed sol-gel reactions of tetraethyl orthosilicate (TEOS) and triethoxysilyl-functionalized polystyrene obtained via atom transfer radical polymerization (ATRP) of styrene, in the presence of citric acid (CA) as non-surfactant template or pore-forming agent and followed by ethanol extraction to remove template molecules. The materials were characterized by infrared spectroscopy OR), N-2 adsorption-desorption measurements, powder X-ray diffraction (XRD), thermogravimetric analysis (TGA) and transmission electron microscopy (TEM). The results indicate that the materials prepared with 50 wt%-60 wt% template contents have average pore sizes of 2-3 nm and large surface areas (ca. 886 m(2)/g) as well as high pore volumes (ca. 0.53 cm(3)/g). The mesoporosity arises from interconnected channels and pores with disordered arrangements. The pore diameters and pore volumes increase as the template content is increased. The pore diameters show a little change upon heating at 200degreesC overnight. However, the materials do not have good hydrothermal stability.

Modelling and Characterization of Basalt/Vinyl Ester/SiC Micro-and Nano-hybrid Biocomposites Properties Using Novel ANN–GA Approach

Basalt fiber reinforcement in polymer matrix composites is becoming more and more popular because of its environmental friendliness and mechanical qualities that are comparable to those of synthetic fibers.Basalt fiber strengthened vinyl ester matrix polymeric composite with filler addition of nano-and micro-sized silicon carbide(SiC)element spanning from 2 weight percent to 10 weight percent was studied for its mechanical and wear properties.The application of Artificial Neural Network(ANN)to correlate the filler addition composition for optimum mechanical properties is required due to the non-linear mechanical and tribological features of composites.The stuffing blend and composition of the composite are optimized using the hybrid model and Genetic Algorithm(GA)to maximize the mechanical and wear-resistant properties.The predicted and tested ANN–GA optimal values obtained for the composite combination had a tensile,flexural,impact resilience,hardness and wear properties of 202.93 MPa,501.67 MPa,3.460 J/s,43 HV and 0.196 g,respectively,for its optimum combination of filler and reinforcement.It can be noted that the nano-sized SiC filler particle enhances most of the properties of the composite which diversifies its applications.The predicted mechanical and wear values of the developed ANN–GA model were in closer agreement with the experimental values which validate the model.

纳米TiO_(2)改性丙烯酸酯增透膜的研究

将丙烯酸酯共聚物与纳米TiO_(2)利用羟基之间的缩合反应形成有机-无机杂化材料,涂覆于聚对苯二甲酸乙二醇酯(PET)薄膜表面后,可提高基体薄膜的透光率,最高可达93.0%,性能优于共混改性材料。此外,薄膜表面接触角也在涂覆后有明显上升。经过热重分析可知,纳米TiO_(2)缩合改性后的杂化材料热分解温度高于纯共聚物和共混改性材料。

Pickering乳液聚合法原位制备杂化乳胶粒子

有机-无机杂化乳胶粒子在涂料、电子、催化和医疗等领域具有广泛的用途。Pickering乳液聚合由固体粒子作为稳定剂稳定两相界面,不需要使用表面活性剂,可以用来制备有机-无机杂化乳胶粒子。本研究使用溶胶凝胶法制备了二氧化硅纳米粒子,并将其用作Pickering乳液聚合的稳定剂,制备有机-无机杂化乳胶粒子。将二氧化硅粒子分别以粉末体系和溶胶体系引入到无皂乳液聚合反应中,系统探讨了单体和引发剂类型、体系pH值等实验条件对杂化乳胶粒子形貌的影响。反应单体与水之间的界面张力对二氧化硅粒子的吸附具有明显影响,较大的界面张力更容易促进二氧化硅粒子在聚合物乳胶粒表面的吸附。本研究结果对于厘清Pickering乳液聚合机理以及无机粒子在两相界面上的吸附机制具有重要价值。

聚苯胺/五氧化二钒插入型杂化纳米复合材料的合成与表征

用原位氧化聚合法将聚苯胺分子链插入层状五氧化二钒的片层中,从而制得了一系列聚苯胺/五氧化二钒(PAn/V2O5)杂化纳米复合材料。采用WAXD、FT-IR、TGA及四探针电导率测量等手段对产物进行表征,结果表明,聚苯胺分子以单层形式在受限的纳米空间(五氧化二钒的片层中)生成,聚苯胺以伸展的单分子链存在,自由电子得到充分离域,PAn/V2O5杂化材料室温电导率在10-3S/cm～10-2S/cm之间。

MMT/PMMA和MMT/PBA/PMMA纳米杂化材料的制备和表征

利用十二烷基苯磺酸钠,钠基蒙脱土和丙烯酸酯类单体通过乳液聚合的方法制备了MMT/PMMA和MMT/PBA/PMMA纳米杂化材料。与钠基蒙脱土有机化后再进行乳液聚合比较发现,直接利用钠基蒙脱土进行乳液聚合同样可以制得与用有机蒙脱土进行乳液聚合结构相似的有机 -无机杂化材料。这样可以省去蒙脱土的有机化处理和烦琐的洗涤过程,大大降低生产成本,缩短工艺过程。通过TEM,XRD等分析手段对制备的杂化材料进行了表征,证明该乳胶粒子具有剥离型结构,并用DSC对该杂化材料的热性能进行了测试,其玻璃化转变温度和起始分解温度均提高 10℃以上,放热量减少约 50%。

高含油量油菜品系T057-7选育方法研究

中国油菜生产上推广的油菜品种含油量普遍较低,提高含油量是目前油菜科研的主要目标之一。河南省农业科学院经济作物研究所利用聚合育种和小孢子培养相结合的育种方法,并采用近红外光谱分析技术对育种材料进行品质检测,选育出了高含油量油菜新品系T057-7。2003年、2004年经农业部油料及制品质量监督检验测试中心检测,T057-7含油量分别为50.15%和52.38%。与油菜细胞质雄性不育系22A和77A测交结果表明,T057-7是细胞质雄性不育系的恢复系。经田间鉴定,T057-7具有农艺性状优良、抗(耐)菌核病、高抗病毒病等优点,可以作为选育高含油量油菜新品种和杂交种的育种材料利用。

环氧-丙烯酸酯混杂光固化体系的研究

研究环氧 -丙烯酸酯混杂光固化体系中引发剂的协同作用 ,证实混杂光固化过程中自由基引发剂对阳离子引发剂二苯基碘盐的增感作用 .混杂光固化膜具有优良的机械性能 ,其抗冲击性能、抗弯曲性能及硬度优于单纯的阳离子体系固化膜 ,与自由基体系固化膜性能接近 ;混杂光固化膜的玻璃化转变温度高于自由基体系固化膜 ;它的耐溶剂性能优异 ,耐丙酮擦拭次数比自由基固化膜高 2 5倍以上 ,比阳离子固化膜高3 .5倍 .这可能是由于混杂光固化过程中形成的 IPN结构造成的 。

SiO_2/PBA/PMMA和CaCO_3/PBA/PMMA核壳结构纳米材料的制备与表征

利用γ 甲基丙烯酰氧丙基三甲氧基硅烷(KH-570)对纳米二氧化硅和纳米碳酸钙有机化处理,红外光谱(FTIR)测试表明,纳米二氧化硅通过有机化处理可以在表面接枝上有机基团,表现在表面处理后波数在2955,2860和1460cm-1有甲基的吸收峰,而纳米碳酸钙由于表面上已有有机基团,表面上没有接枝上新的有机基团。然后利用乳液聚合的方法制备了以表面处理过的纳米二氧化硅或纳米碳酸钙为核,丙烯酸丁酯和甲基丙烯酸甲酯为壳的有机-无机杂化材料。用凝胶渗透色谱(GPC)测定了其各种相对分子质量及其相对分子质量分布后发现,加入纳米碳酸钙后其相对分子质量有所降低,相对分子质量分布变宽;加入纳米二氧化硅后其相对分子质量有所增大,相对分子质量分布变窄。透射电镜(TEM)和粒度分布仪测试表明,乳液聚合前粒子大部分以团聚体的形式存在,粒径在1～2μm左右;乳液聚合后粒子大部分以纳米尺寸存在,粒径10～200nm。实验证明,乳液聚合是制备有机-无机纳米杂化材料非常有效的方法。

混杂光固化体系的原理及应用

混杂光固化或双重固化是指在同一体系中采用两种或两种以上不同类型的聚合反应来使体系固化的方法 ,它是原位改性高分子的一种新方法 .混杂光固化体系包括自由基 阳离子混杂光固化体系、自由基 缩聚混杂体系和自由基 自由基混杂体系等 .