Poly(methylmethacrylate)-silica nanocomposites films from surface-functionalized silica nanoparticles

Poly(methylmethacrylate)-silica nanocomposite films were prepared from copolymerizing methylmethacrylate with allylglycidylether-functionalized silica nanoparticles. No alkoxysilane coupling agents and sol-gel reactions were employed in this preparation approach to result in nanocomopsite films having silica contents higher than 70 wt%. Good transparency, hardness above 9H grade, and superior surface planarity were observed with the prepared naocomposite films. Glass transition temperatures were not observed with the nanocomposite films by DSC measurement to indicate their good thermal and dimensional stability.     

Solid-state organization of poly(methylmethacrylate)-poly(methylphenylsiloxane) based interpenetrating networks

Three interpenetrating networks based on polymethylphenylsiloxane (PMPS) and polymethylmethacrylate (PMMA) with different compositions were prepared. They were investigated using differential scanning calorimetry (DSC) and high-resolution solid-state ¹³C NMR techniques, in order to study the heterogeneous character of the domains involved in these materials at the nanoscopic scale. DSC observed broad glass transitions of the PMPS chains. ¹³C cross-polarization (CP) experiments clearly showed that the aromatic PMPS carbons have a rate of CP which is composition dependent, indicating that PMPS and PMMA chains are interpenetrating at a very low spatial scale. These results were supported by T_1ρ(¹H) and ¹³C line width measurements as a function of temperature. Moreover, T_1ρ(¹H) measurements indicated that PMMA chains are rather homogeneously distributed whereas PMPS chains belong either to interpenetrating domains or to PMPS-rich domains.     

Polyaniline/poly(methylmethacrylate) blends for corrosion protection: The effect of passivating dopants on different metals

This paper describes the mechanism concerning active corrosion protection of metals using different conducting blends, formed by doped polyaniline (PANI) and poly(methylmethacrylate) (PMMA). Electrochemical and spectroscopic techniques are used to investigate the influence of two different dopants of PANI on the anticorrosion performance for different metals: camphorsulfonic (HCSA) and phenylphosphonic acids (HPPA). Moreover, it was also carried out a structural characterization of conducting blends and the analysis of the passive films formed as a consequence of the redox reaction between PANI and the metal substrates. In all the metal/blend systems, a potential shift to more positive values than the potential of uncoated metals in acid solution is observed, indicating the protection of the metal substrate. Moreover, Raman microscopy technique showed a clear diminution of the oxidation number of the conducting polymer in the blends and also the presence of a second passive layer formed by counter ions released from PANI and different metal cations.     

Improvement of Permeability of Poly(vinyl alcohol) Hydrogel by Using Poly(ethylene glycol) as Porogen

The porous structure of PVA hydrogel achieved with varying content and varying molecular weight of PEG was investigated. It was found that with increasing content or molecular weight of PEG, the diffusion coefficient D _e and UV transmission of ink solution increased, indicating that the permeability and mass transfer capability of the gel beads were enhanced. The swelling rate constant k and equilibrium swelling rate of the gel were significantly improved by addition of PEG, and many pores formed inside the gel to provide channels for microbial metabolites. With increasing molecular weight of PEG, the size of pores became increasingly large.     

Morphology and Dielectric Properties of Polyhydroxybutyrate (PHB)/Poly(methylmethacrylate)(PMMA) Blends with Some Antimicrobial Applications

Poly(3-hydroxy)butyrate (PHB) is a microbial polyester, which provides the advantages of biodegradability and biocompatibility but it is brittle and has low abilities for some chemical modifications. To overcome such problems reactive blending was done with a glassy acrylic polymer, poly(methylmethacrylate) (PMMA) with different compositions. The dielectric response of PHB/PMMA blend with different compositions were investigated as a function of frequency and at different temperatures. The results revealed the existence of single a-relaxation process indicating the miscibility of amorphous fractions of PHB and PMMA. Also the morphological study of such blends doesn't show macro phase separation of PMMA on the surface scan which may be attributed to the compatibility in melt between PHB and PMMA particles in the PHB matrix. The biological activity of such investigated systems against some pathogenic microorganisms was found to increase by increasing the amount of PMMA in the blend     

聚对苯硫醚、聚间苯硫醚及其共聚物的合成与表征

用硫磺、对二氯苯和间二氯苯为原料,在极性有机溶剂六甲基磷酰三胺中合成了聚对苯硫醚(p-PPS)、聚间苯硫醚(m-PPS)及其共聚物.用裂解气相色谱、红外光谱、X-射线衍射及热分析对所得聚合物的结构和热性能进行了初步研究.结果表明:p—PPS和m—PPS都是结晶性聚合物,间位结构引入到p-PSS的结构中明显地破坏了p-PPS的高度结晶性,降低了耐热性,但最大失重速率处温度却无多大变化.这一共聚改性途径可望用于改进p—PPS的刚性,提高其韧性.     

The effect of the distance between neighboring vinyl groups on template polymerization

Intra-molecular polymerization of methacrylate type multi-vinyl monomer of Noria (Noria-MVM) was investigated from the viewpoint of the structure of Noria-MVM. Noria-MVM was polymerized by atom transfer radical polymerization (ATRP) with different reaction time, temperature, and monomer concentration. Polymerized sequences were derived from polymerized Noria-MVM by hydrolysis and methylation. The degree of polymerization (DP) of polymerized sequence was determined by matrix-assisted laser desorption/ionization time-of-flight mass (MALDI-TOF mass) analyses. The DP values were odd value in a range of 3-23. The distance from radical to the next vinyl group was influenced by the structure of Noria. When the distance was shorter than 5 Å, the polymerization did not terminate. When the distance was longer than 5 Å, the termination tended to occur.     

羟基丁酸-戊酸共聚物与聚丙烯酸丁酯的反应性共混

采用反应性共混的方法对羟基丁酸－戊酸共聚物进行改性,使具有生物活性的丙烯酸丁酯在羟基丁酸－戊酸共聚物上接枝聚合,达到提高产物机械性能的同时,保持其生物降解性的目的。系统地研究了反应条件和改性物配比对产物接枝率及共混材料相容性等的影响,发现加料顺序和丙烯酸丁酯用量对产物的接枝率和相容性有很大影响,丙烯酸丁酯含量为２０％～３０％,产物接枝率最高可达２０％以上;在加工时填充４％～６％的滑石粉补强,羟基丁酸－戊酸共聚物／丙烯酸丁酯复合材料的机械性能明显提高。     

Modification of Waste Poly(Ethylene Terephthalate) (PET) by Using Poly(L-Lactic Acid) (PLA) and Hydrolytic Stability

The purpose of this study is the preparation of hydrolytically degradable copolymers of waste poly(ethylene terephthalate) (PET). To achieve this, we modified PET by using biodegradable poly(lactic acid) (PLA). Modification reactions were carried out in o-nitrophenol as solvent at 140 and 170°C for 8, 16, and 24 h in the presence of dibutil tin oxide (DBTO) as catalyst. The amount of the total polymers (PLA and PET) in the reaction mixture was 30% by weight, and the weight ratios of PLA/PET were 10/90, 50/50, and 90/10. These modified products were characterized by Fourier transform infrared spectrometer (FTIR), differential scanning calorimeter (DSC) as well as by hydrolytic degradation determinations. Hydrolytic degradations of the products were determined gravimetrically. Disc-shaped samples were placed in tubes containing phosphate buffer solution of pH 7.2 and kept in a water bath at 60°C for 28 days. The weight loss of the products after hydrolytic degradation ranged from 1.25% to 48.75% after 28 days.     

Kaolinite, montmorillonite, and their modified derivatives as adsorbents for removal of Cu(II) from aqueous solution

Adsorption of metals by clay minerals is a complex process controlled by a number of environmental variables. The present work investigates the removal of Cu(II) ions from an aqueous solution by kaolinite, montmorillonite, and their poly(oxo zirconium) and tetrabutylammonium derivatives. The entry of ZrO and TBA into the layers of both kaolinite and montmorillonite was confirmed by XRD measurement. The specific surface areas of kaolinite, ZrO-kaolinite, TBA-kaolinite, montmorillonite, ZrO-montmorillonite, TBA-montmorillonite were 3.8, 13.4, 14.0, 19.8, 35.8 and 42.2 m²/g, respectively. The cation exchange capacity (CEC) was measured as 11.3, 10.2, 3.9, 153.0, 73.2 and 47.6 meq/100 g for kaolinite, ZrO-kaolinite, TBA-kaolinite, montmorillonite, ZrO-montmorillonite, TBA-montmorillonite, respectively. Adsorption increased with pH till Cu(II) ions became insoluble in alkaline medium. The kinetics of the interactions suggests that the interactions could be best represented by a mechanism based on second order kinetics (k₂ = 7.7 × 10⁻² to 15.4 × 10⁻² g mg⁻¹ min⁻¹). The adsorption followed Langmuir isotherm model with monolayer adsorption capacity of 3.0–28.8 mg g⁻¹. The process was endothermic with ΔH in the range 29.2–50.7 kJ mol⁻¹ accompanied by increase in entropy and decrease in Gibbs energy. The results have shown that kaolinite, montmorillonite and their poly(oxo zirconium) and tetrabutyl-ammonium derivatives could be used as adsorbents for separation of Cu(II) from aqueous solution.     

含PEG组分的聚(N-异丙基丙烯酰胺)水凝胶的制备研究

首先合成了二丙烯酰基封端的聚乙二醇(PEG)大分子交联剂,然后使其与N,N-亚甲基双丙烯酰胺(BIS)和(N-异丙基丙烯酰胺)(NIPAM)单体进行交联反应,制备了PNIPAM-co-PEG-co-BIS水凝胶。与通常的PNIPAM-co-BIS凝胶比较,PNIPAM-co-PEG-co-BIS凝胶显示了明显加速的去溶胀动力学。这种加速的去溶胀性能归因于凝胶中的PEG组分为凝胶提供了亲水通道,在缩水过程中有利于凝胶的脱水。     

Application of Poly(butylenes 2-methylsuccinate) as Migration Resistant Plasticizer for Poly(vinyl chloride)

The bio-based and biodegradable polyester poly(butylenes 2-methylsuccinate) (PBM) was successfully used as a polymeric plasticizer to modify poly(vinyl chloride) (PVC) in this work. The tensile properties, plasticization efficiency estimated by the lowered glass transition temperature and the enhanced elongation at break of the PVC/PBM blends and the migration stability of the PBM were investigated. It was indicated that the migration-resistant property of PVC plasticized with PBM was greatly superior to that with dioctyl phthalate (DOP). Furthermore, the tensile properties were comparable to that of PVC/DOP, indicating that the environmentally friendly PBM can be used as an alternative plasticizer to remove the potential health risks from migrating phthalates during applications.     

Preparation and Characterization of Poly(benzimidazole-amide)/ZnO Nanocomposites Using Silane Coupling Agent

Some novel nanocompoites were fabricated via zinc oxide (ZnO) nanoparticles which was modified by 3-aminopropyltriethoxylsilane (KH550) as a coupling agent. Poly(benzimidazole-amide) (PBIA) was synthesized via polymerization reaction of 1,3-bis(5-amino-1H-benzimidazol-2-yl)benzene (3a) with isophthaloyl chloride (4b) and used as a polymer matrix. PBIA/ZnO nanocompoites were characterized by Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). FE-SEM and TEM analysis showed that the modified ZnO nanoparticles were homogeneously dispersed in polymer matrix. In addition, thermogravimetric analysis (TGA) data indicated an enhancement of thermal stability of nanocomposite compared with the pure polymer.     

Latent Heat Enhancement of Paraffin Wax in Poly(divinylbenzene-co-methyl methacrylate) Microcapsule

The preparation of divinylbenzene (DVB)-methyl methacrylate (MMA) copolymer microcapsule encapsulated Rubitherm27 (RT27) P(DVB-co-MMA)/RT27 used as heat storage material by the microsuspension polymerization was studied to improve the latent heats of the encapsulated RT27 with sufficient polymer shell strength. Percent loading of RT27 and DVB:MMA ratio were optimized. The optimal condition was 30% loading of RT27 and 30:70 (% w/w) of DVB:MMA ratio. The nonspherical microcapsules with a dent having core-shell morphology were obtained. The thermal properties of the encapsulated RT27 in the P(DVB-co-MMA)/RT27 capsules were measured by thermogravimetric analyzer and differential scanning calorimeter. The heats of melting (ΔH_m; 153 J/g-RT27) and crystallization (ΔH_c; 164 J/g-RT27) of the encapsulated RT27 in the prepared copolymer capsules were higher than those in PDVB and closed to those of bulk RT27 (162 and 168 J/g-RT27 for ΔH_m and ΔH_c, respectively).     

Study on the Crystallization Kinetic and Characterization of Poly(lactic acid) and Poly(vinyl alcohol) Blends

In this study, poly(lactic acid) (PLA) and poly(vinyl alcohol) (PVA) blends, with PLA/PVA mass ratios of 100/0, 90/10, 80/20, 70/30, 60/40, 50/50, and 40/60, were prepared by means of the melt blending method. The result of torque measurements and thermal gravimtric analysis tests showed that the addition of PLA can decrease the melt viscosity of PVA and that the second degradation step of PVA nearly disappeared for the PLA₈₀/PVA₂₀ blend. The absorbance peaks of the carbonyl group and the hydroxyl group in the Fourier transform infrared spectra of PLA/PVA blends had significant shifts to lower wave numbers, indicating that there were interactions between these two groups. Combined with the result of the differential scanning calorimetry curves, this interaction would be favorable for improving miscibility. The X-ray diffraction patterns and the polarized light microscope (PLM) micrographs showed that PVA can serve as a nucleating agent to promote the crystallization of PLA in PLA/PVA blends. Moreover, the PLA₈₀/PVA₂₀ blend gave the highest growth rate of PLA spherulite.     

Dynamics of Poly(ethylene glycol)-Tethered, pH Responsive Networks

Smart biomaterials composed of pH responsive polymers, poly((meth)acrylic acid), were synthesized using a precipitation polymerization technique. The microparticles were grafted with poly(ethylene glycol) (PEG) chains that are capable of complexing with the hydroxyl groups of the polyacid and interpenetrating into the mucus gel layer upon entry into the small intestine. Upon introduction of an alkaline solution, these materials imbibe a significant amount of water and create a highly viscous suspension. These materials have the necessary physicochemical properties to serve as mucoadhesive controlled release drug carriers for the oral delivery of drugs.     

Novel Poly(3-hydroxyoctanoate)/Poly(3-hydroxybutyrate) blends for medical applications

Novel Poly(3-hydroxybutyrate)/Poly(3-hydroxyoctanoate) blends were developed with varying amounts of Poly(3-hydroxyoctanoate), P(3HO) and Poly(3-hydroxybutyrate), P(3HB) for their potential use in various medical applications. These blend films exhibited higher tensile strength and Young’s modulus values compared to neat P(3HO). The overall protein adsorption and % cell viability was also found to be significantly higher in the blend films than the neat P(3HO) film. Hydrolytic degradation was faster in the blend films and the degradation rate could potentially be tailored to achieve the optimum rate required for a particular medical application. Hence, these novel blends were found to be highly biocompatible with surface, mechanical and thermal properties suitable for a range of potential medical applications, a great step forward in the area of medical materials.     

Synthesis and physicochemical characterization of a well-defined poly(butadiene 1,3)-block-poly(dimethylsiloxane) copolymer

For the first time, order-order and order-disorder transitions were detected and characterized in a model diblock copolymer of poly(butadiene-1,3) and poly(dimethylsiloxane) (PB-b-PDMS). This model PB-b-PDMS copolymer was synthesized by the sequential anionic polymerization (high vacuum techniques) of butadiene 1,3 (B) and hexamethylciclotrisiloxane (D₃), and subsequently characterized by nuclear magnetic resonance (¹H and ¹³C NMR), size exclusion chromatography (SEC), Fourier Transform infrared spectroscopy (FTIR), Small-Angle X-ray scattering (SAXS) and rheology. SAXS combined with rheological experiments shows that the order-order and order-disorder transitions are thermoreversible. This fact indicates that the copolymer has sufficient mobility at the timescale and at the temperatures of interest to reach their equilibrium morphologies.     

热塑性聚（氨酯—酰亚胺）的结构与性能

本文以均苯四甲酸二酐、二苯甲烷二异氰酸酯、一缩二乙二醇、二苯基硅二醇和双酚Ａ为单体、Ｎ－甲基－２－吡咯烷酮为溶剂，采用前文报导的方法分别合成了七种不同主链结构和酰亚胺环含量的热塑性聚。考察了各咱性能，研究了降解历程，提出了热塑性聚第一阶段热分解失重的两种机理：主链断裂失重机理和侧基苯环脱除失重机理。     

Effects of europium (III) acetylacetonate doping on the miscibility and photoluminescent properties of polycarbonate and poly(methyl methacrylate) blends

Blends stand out as simple and cheap materials with unique properties. The miscibility of blends formed by bisphenol-A polycarbonate (PC) with poly(methyl methacrylate) (PMMA) doped with europium (III) acetylacetonate have been studied by differential scanning calorimetry (DSC), infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and photoluminescent (PL) spectroscopy. DSC studies demonstrated that undoped PC/PMMA blends obtained by precipitation method present one glass transition temperature, evidencing their apparent miscibility. FTIR spectra revealed synergic effects in the PC/PMMA system as well as the incorporation of the Eu³⁺ complex. TGA analysis suggested that the Eu³⁺ complex remains preferably in the PC micro-phase. SEM analysis showed that europium (III) acetylacetonate is homogeneously distributed within the blend and PL spectra evidenced the photoluminescence of Eu³⁺ incorporated into the blend.