Influence of a pore-forming agent on swelling,network parameters,and permeability of poly(ethylene glycol)-crosslinked poly(methyl vinyl ether-co-maleic acid) hydrogels: Application in transdermal delivery systems

We characterized hydrogels, prepared from aqueous blends of poly(methyl vinyl ether-co-maleic acid) (PMVE/MA) and poly(ethylene glycol) (PEG 10,000 Daltons) containing a pore-forming agent (sodium bicarbonate, NaHCO₃). Increase in NaHCO₃ content increased the equilibrium water content (EWC) and average molecular weight between crosslinks (M_c) of hydrogels. For example, the %EWC was 731, 860, 1109, and 7536% and the M_c was 8.26, 31.64, 30.04, and 3010.00 × 10⁵ g/mol for hydrogels prepared from aqueous blends containing 0, 1, 2, and 5% w/w of NaHCO₃, respectively. Increase in NaHCO₃ content also resulted in increased permeation of insulin. After 24 h, percentage permeation was 0.94, 3.68, and 25.71% across hydrogel membranes prepared from aqueous blends containing 0, 2, and 5% w/w of NaHCO₃, respectively. Hydrogels containing the pore-forming agent were fabricated into microneedles (MNs) for transdermal drug delivery applications by integrating the MNs with insulin-loaded patches. It was observed that the mean amount of insulin permeating across neonatal porcine skin in vitro was 20.62% and 52.48% from hydrogel MNs prepared from aqueous blends containing 0 and 5% w/w of NaHCO₃. We believe that these pore-forming hydrogels are likely to prove extremely useful for applications in transdermal drug delivery of biomolecules. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

The effect of capping with natural and modified zeolites on the release of phosphorus and organic contaminants from river sediment

A microcosm system that included river sediment, water and different zeolite capping materials (natural zeolite, surfactant-modified zeolite (SMZ), or aluminum modified zeolite (AMZ)) was designed to study the effect of capping on the release of phosphorus and three organic pollutants (phenol, pyridine, and pyrene) from the sediment to the overlying water over the course of three month. For the same amount of the three capping materials, the efficiency of phosphorus inactivation was in the order of SMZ>AMZ>natural zeolite. The inactivation of phosphorus was mainly caused by the covering effect, co-precipitation and adsorption by the capping materials. The different zeolites gave different results for the release of phenol, pyridine, and pyrene from the sediment. When natural zeolite was used as the capping material, there was no effect on the release of pyrene and pyridine, whereas capping the sediment with SMZ or AMZ inhibited the release of pyrene and pyridine but to different extents. However, for controlling the release of phenol from the sediment, aluminum modified zeolite was the most efficient material, whereas no effects were observed when natural zeolite or SMZ were used. The different capabilities of the zeolite materials for controlling the release of different organic pollutants are related to the differences in the electrical properties of these pollutants.     

醋-丙乳胶纳米建筑涂料配制及性能研究

以醋-丙乳胶为粘接剂，在传统建筑涂料配方基础上，加入经表面处理的纳米TiO2、SiO2，制得了醋-丙乳胶纳米建筑涂料。探讨了纳米TiO2、SiO2平均粒径对涂膜耐人工老化性能的影响，研究了纳米TiO2、SiO2及其混合体添加量对制得的建筑涂料性能的影响。研究结果表明．TiO2、SiO2粉体平均粒径在200nm以下，涂膜的耐人工老化性能有很大改善。在100nm以下，涂膜耐人工老化性能较为理想，且加入纳米混合粉体涂膜的耐人工老化性能最佳；纳米粉体质量分数在2．0％～3．0％范围内．涂膜综合性能较佳，且能较好地满足外墙建筑涂料技术指标要求。     

Investigation on crystallization behavior and hydrophilicity of poly(vinylidene fluoride)/poly(methyl methacrylate)/poly(vinyl pyrrolidone) ternary blends by solution casting

Ternary blends composed of matrix polymer poly(vinylidene fluoride) (PVDF) with different proportions of poly(methyl methacrylate) (PMMA)/poly(vinyl pyrrolidone) (PVP) blends were prepared by solution casting. The crystallization behavior and hydrophilicity of ternary blends were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), wide angle X‐ray diffraction (WAXD), differential scanning calorimetry (DSC), and contact angle test. According to morphological analysis, the surface was full of typical spherulitic structure of PVDF and the average diameter was in the order of 3 μm. The samples presented predominantly β phase of PVDF by solution casting. It indicated that the size of surface spherulites and crystalline phase had little change with the PMMA or PVP addition. Moreover, FTIR demonstrated special interactions among the ternary polymers, which led to the shift of the carbonyl stretching absorption band of PVP. On the other hand, the melting, crystallization temperature, and crystallinity of the blends had a little change compared with the neat PVDF in the first heating process. Except for the content of PVP containing 30 wt %, the crystallinity of PVDF decreased remarkably from 64% to 33% and the value of t_1/2 was not obtained. Besides, the hydrophilicity of PVDF was remarkably improved by blending with PMMA/PVP, especially when the content of PVP reached 30 wt %, the water contact angle displayed the lowest value which decreased from 98.8° to 51.0°. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

改性剂对白炭黑/叶腊石补强SBR性能的影响

研究了白炭黑/叶腊石并用比及改性剂种类对丁苯橡胶性能的影响。结果表明,叶腊石的补强性不如白炭黑,但加工性能优于白炭黑;在白炭黑/叶腊石复合补强丁苯橡胶中,改性剂的加入可以有效地改善胶料的加工性能,提高胶料的硫化速度和物理机械性能。其中偶联剂Si-69的改性效果最好,加工助剂L-12的改性效果不明显。     

Assessment on the mechanical,structural, and thermal attributes of green graphene-based water soluble polymer electrolyte composites

In the current study, graphene oxide (GO) was prepared using green chemistry with modified Hummer's method without incorporating sodium nitrate (NaNO₃). Solvent casting was employed to fabricate GO-doped poly(ethylene oxide) (PEO), that is, PEO/GO composites with various proportion of Na₂SO₄ and were then subjected to characterization via advanced spectroscopic techniques for different physicochemical aspects to estimate their potential applications as marketable products. XRD analysis explored that fabricated composites are more crystalline than neat PEO. PEO/GO/Na₂SO₄ composite films offered maximum crystallinity. SEM displayed the same trend. TG/DTA thermogram exposed better thermal stability than pristine polymer. FTIR studies confirmed complexation among hybrid's components. Elongation-at-break and Young's modulus displayed an enhancing behavior with an incremental loading of salt and filler. In terms of mechanical performance, composite of PEO with 0.37 wt % GO and 0.08 g salt was found to be an ideal composition during the course of study. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48376.     

Influence of poly(phosphoric acid) on the properties and structure of ethylene–vinyl acetate‐modified bitumen

Ethylene–vinyl acetate (EVA) modified (EM) bitumen was modified further by the addition of poly(phosphoric acid) (PPA). Owing to the gelation and acidification effect of PPA, the high‐temperature properties and compatibility of EM bitumen were improved greatly. Part dissolution of EVA after acidification was confirmed by the viscous behavior of EVA/PPA‐modified (EPM) bitumen in rheological tests to some extent. Morphology observation illustrated the decomposition of EVA in bitumen after PPA modification and ageing. Fourier transform infrared analysis proved that the hydrolysis reaction took place between the vinyl acetate segment of EVA molecule and the extra hydrogen protons of PPA. Thermal analysis displayed the thermodynamic behaviors of EM and EPM bitumens before and after ageing and confirmed the part dissolution of EVA further after PPA acidification. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46553.     

共沉淀法修饰二氧化钛微粒及其杀菌性能研究

以硫酸氧钛(TiOSO4)为原料，银为修饰剂，采用液相共沉淀法修饰TiO2微粒。以TEM，XRD，GBl5979-1995等方法对二氧化钛微粒的结构、组成、晶粒大小、杀菌性能进行了研究。结果表明，二氧化钛微粒为锐钛型；微粒大小在80～150nm范围；杀菌性能好，对金黄色葡萄球菌、大肠杆菌、白色念珠菌在5min内在菌浓度为1％(质量分数，下同)时的杀菌率均达到99．90％以上。经银修饰的二氧化钛微粒可作为无机杀菌剂应用于杀菌或抗菌织物、涂料、塑料、化妆品等。     

Adsorption of surfactant by hydrophobically modified poly[2‐(diethylamino)ethylmethacrylate‐co‐N‐vinyl‐2‐pyrrolidone/octadecyl acrylate)] hydrogels and effect of surfactant adsorption on the volume phase transition

Hydrophobically modified poly[2‐(diethylamino)ethylmethacrylate‐co‐N‐vinyl‐2‐pyrrolidone/octadecyl acrylate) [P(DEAEMA‐co‐NVP/OA)] hydrogels were synthesized by free‐radical crosslinking copolymerization of 2‐(diethylamino)ethylmethacrylate (DEAEMA), N‐vinyl‐2‐pyrrolidone (NVP) with different amounts of hydrophobic comonomer octadecyl acrylate (OA) in tert‐butanol with ethylene glycole dimethacrylate (EGDMA) as a crosslinker. The swelling equilibrium of the hydrogels was investigated as a function of temperature and hydrophobic comonomer content in aqueous solutions of the anionic surfactant sodium dodecyl sulfate (SDS) and the cationic surfactant dodecyltrimethylammonium bromide (DTAB). The results indicated that the swelling behavior and temperature sensitivity of the hydrogels were affected by the type and concentration of surfactant solutions. Additionally, the amount of the adsorbed SDS and DTAB molecules onto the hydrogels was determined by fluorescence measurements. An increase of OA content in the hydrogel caused an increase in the amount of adsorbed surfactant molecules in both media. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3771–3775, 2007     

不同沉淀剂对Li_(1.1)Ni_(0.5)Mn_(0.5)O_2结构和电化学性能的影响

通过共沉淀-高温煅烧方法合成了层状结构的Li1.1Ni0.5Mn0.5O2正极材料,并通过XRD、SEM研究了不同沉淀剂对产物结构和形貌的影响。运用恒电流充放电测试、CV及EIS研究了其电化学性能。结果表明,不同沉淀剂合成的产物均具有良好的层状结构及形貌。碳酸盐为沉淀剂合成的产物锂镍混排度最小,颗粒更均匀,具有最低的极化及最小的电荷转移阻抗,具有最高的容量及最优的倍率性能。     

Influence of water and magnesium ion on the optical properties in various plasticized poly(vinyl butyral) sheets

The study is focused on influences of optical properties change of poly(vinyl butyral) (PVB) sheets determined for safety glass preparing. Optic measurements were evaluated itself and after, the laminated glass was observed. The study deals with a cognizance of causation of the optical properties change in different PVB sheets in dependence on adsorbed water content into the polymer matrix. Results of this work describe the influence of ? OH group content on PVB chain and type and amount of additives adjusting adhesion of PVB towards glass. However, the most important discovery of this work is evaluation of critical water content that leads to haze generation. The evaluation of various types of sheets was performed. At the same time the artificial addition of Mg²⁺ salts of organic acids (with various polarity of the molecule) was evaluated to assess their influence on haze generation. It was found that haze caused by Mg²⁺ salt is possible to eliminate when there is certain water content in PVB. Obtained values and comparisons are very important for PVB sheets industry and for industry dealing with lamination of PVB between glasses. Influence of these factors and comparison of haze generation for various PVB sheets has not been published yet. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

发泡剂对人造革发泡倍率与泡孔结构的影响

对比分析了纯放热性发泡剂AC与吸－放热复合发泡剂DDL－105的分解与发泡特性。详细比较了以这两类发泡剂在相同配方和加工条件下样品的发泡倍率、泡孔结构差别以及对温度和时间的依赖关系。     

Development of nanocomposites based on organically modified montmorillonite and plasticized PVC with improved barrier properties

Montmorillonite (MMT) was organically modified with tributyl citrate (TBC). Organoclays (OMMTs) were processed with diisononyl phthalate (DINP)‐plasticized polyvinyl chloride (PVC) to form polymer nanocomposites. The produced composite materials showed a contradictory change in properties to that expected of a layered silicate nanocomposite, with a decreased E‐modulus and increased gas permeability compared with a material without OMMT. It was experimentally shown that the TBC modifier was extracted from the OMMT and was dispersed in the PVC/DINP matrix, whereupon the OMMT collapsed and formed micrometer‐sized agglomerates. Further investigation revealed that TBC has a significant effect on the gas permeability and the E‐modulus, even at low additions to a DINP‐plasticized PVC. A PVC nanocomposite with the TBC acting as both the OM for MMT and as the primary plasticizer was produced. This material showed a significantly increased E‐modulus as well as a decrease in gas permeability, confirming that it is possible to develop a nanocomposite based on plasticized PVC, if both the organo‐modification of the MMT and the formulation of the matrix are carefully selected. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42876.     

Influence of post‐treatments on the properties of porous poly(vinyl alcohol) membranes

Porous poly(vinyl alcohol) (PVA) membranes were prepared by a phase‐inversion method. The influence of chemical crosslinking and heat treatments on the swelling degree, resistance to compaction, mechanical strength, and morphology of porous PVA membranes was extensively studied. The crosslinking degree and crystallinity of the membranes, calculated from IR spectra, increased with the treatment time. The porosity, calculated on the basis of swelling experiments, showed a decreasing trend for heat‐treated membranes but remained almost at a constant value for crosslinked membranes. Such a change was further proved with scanning electron microscopy pictures. The behavior was explained by the rearrangement of PVA chains during the heat‐treatment process, which led to morphological changes in the membranes. The mechanical properties of the porous membranes in dry and wet states were measured, and a great difference was observed between crosslinked and heat‐treated membranes in the dry and wet states. The crosslinked membranes showed good mechanical properties in the dry state but became fragile in the wet state. On the contrary, the heat‐treated membranes were more flexible in the wet state than in the dry state. This change was explained by the turnaround of inner stress in the systems during the swelling process. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Investigation on the interpenetrating polymer networks (ipns) of polyvinyl alcohol and poly(N-vinyl pyrrolidone) hydrogel and its in vitro bioassessment

Poly(vinyl alcohol) (PVA) and poly(N-vinyl pyrrolidone) (PVP) composite hydrogel with interpenetrating polymer networks (IPNs) was prepared by in situ polymerization and compared with pure PVA hydrogel. The prepared IPN hydrogel was characterized by infrared spectroscopy (IR), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy. The mechanical property and cell culture were also tested. The results show that PVP can chemically bond with PVA and form uniform blend hydrogel. The content of PVP can affect the structure, crystallinity, glass transition temperature (T_g), and mechanical property of the hydrogel. The T_g of the PVA hydrogel is 2.7°C while the T_g of the IPN hydrogel is −37°C. The IPN hydrogel has lower glass transition temperature, corresponding to better elastic properties, and has better mechanical performance on stretch and compression than PVA hydrogel. The crystallinity (X_c) of PVA hydrogel and IPN hydrogel is 65.3 and 26.3%, respectively. The DMA curves and XPS analysis suggest that PVA and PVP are well miscible on a molecular level in the IPN hydrogel. The cell proliferation trend demonstrates that the addition of PVP has a positive influence on the cell growth and the IPN hydrogel may be used as a promising biomaterial for artificial cartilage substitute. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

氧化镁和氧化锌对PVC的热稳定作用研究

用HAAKE流变仪评价了氧化镁和氧化锌的热稳定作用。研究结果表明,氧化锌具有较好的初期稳定作用,但对长期热稳定反而不利;氧化镁的作用则相反。用不同规格的氧化镁和氧化锌的研究还表明,不同规格氧化镁主要影响PVC的初期色相,而不同规格氧化锌对初期和长期稳定性都有影响。最后,不同温度条件下的测试表明,采用这种稳定体系时,设备的温度不宜超过180℃。     

Phase‐separation prevention and performance improvement of poly(vinyl acetate)/TEOS hybrid using modified sol‐gel process

The formation of covalent bonds between silanols in copolymer and those in silica prevents organic–inorganic phase separation. Two series of hybrid composite materials, poly(vinyl acetate‐co‐vinyl trimethoxysilane)/TEOS and poly[vinyl acetate‐co‐3‐(trimethoxysilyl)propyl methacrylate]/TEOS, were fabricated using a modified sol‐gel process. The hybrids were transparent. Two kinds of silane coupling agents, vinyl trimethoxysilane (VTS) and 3‐(trimethoxysilyl)propyl methacrylate (γ‐MPS), were used to prevent macrophase separation through formation of covalent bonds. Thermal analysis showed that γ‐MPS was more effective than VTS for the formation of covalent bonds. Enhancement of thermal stability of the hybrids was investigated by thermogravimetric analysis. Photomicrographs of scanning electron microscopy and images of atomic force microscopy indicated that inorganic silica particles were homogeneously dispersed in less than 50 nm in organic matrix. The morphological properties of hybrids were strongly dependent on the organic–inorganic composition. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2310–2318, 2001     

Influence of additional thermal stabilizers on the reprocessing of postconsumer poly(vinyl chloride) bottles

The addition of heat stabilizers is essential for preventing the degradation of poly(vinyl chloride) (PVC) during its processing. The heat stabilizers consumed in the first run have to be made up before the reprocessing of recycled PVC. In this study, solvent‐cast films, which were prepared from granulated postconsumer PVC bottles mixed with plasticizers and thermal stabilizers, were used. The films were subjected to various heat treatments. No considerable structural change upon heat treatments at 140–160°C was found in IR and differential scanning calorimetry analyses. Polyene formation observed through ultraviolet analysis was not severe, indicating that the added stabilizers worked well in preventing degradation. The weight loss during the heat treatments was attributed partly to the decomposition of PVC and the evaporation of volatile components and mainly to the removal of the solvent upon heating. Although this study was conducted with water bottles that were to be recycled, it may be equally well applied to other similarly formulated PVC‐based materials, such as packaging films. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3994–3999, 2003     

Poly(vinyl chloride)/metallic oxides/organically modified montmorillonite nanocomposites: Preparation,morphological characterization,and modeling of the mechanical properties

Poly(vinyl chloride), metallic oxides (from copper, molybdenum, and zinc), and organically modified montmorillonite (O‐MMT) nanocomposites were prepared in a melt‐blending or intercalation‐in‐the‐molten‐state process. The morphology of the nanocomposites was evaluated with X‐ray diffraction (XRD) and transmission electron microscopy (TEM). Properties, such as the mechanical, thermal, and electrical properties, and the dynamic thermal stability against dehydrochlorination were also evaluated. Nanocomposites with a hybrid intercalated/exfoliated structure were obtained in all of the situations considered, as demonstrated by the XRD and TEM results and indirectly by the increment of Young's modulus of the formulations with increasing amount of O‐MMT incorporated. The modeling of Young's modulus by the Halpin–Tsai, Hui–Shia, and Lewis–Nielsen theories showed that the process of nanocomposite preparation allowed the aspect ratio of the clay particles to increase; these values were comparable to those nanocomposites obtained by other researchers with different polymeric matrices and methodologies. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Studies on mechanical and rheological properties of poly(vinyl chloride) modified with elastomers and rigid organic particles

Chlorinated polypropylene (CPP) as rigid organic particles and chlorinated polyethylene (CPE) as elastomer were used to modify the properties of poly(vinyl chloride) (PVC) by melt blending. Both mechanical and rheological properties of the PVC blends were investigated. The submicroscopic morphology of the blends was observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results demonstrate that when the weight ratio of CPE to CPP is about 6 : 1, a sample with the best impact strength and without obvious decline in tensile strength can be obtained. The impact strength correlates well with SEM morphologies, and TEM micrographs in the necking of the tensile specimen indicate that a cold‐drawing deformation of rigid particles happens as reported by T. Kurauchi and T. Ohta (J Mater Sci 1984, 19, 1699). Therefore, a conclusion can be drawn that CPP particles acting similar to elastic particles can toughen PVC, and the cold‐drawing deformation is the primary reason for toughening the PVC blends. In addition, the addition of CPP can promote the processibility of PVC ternary blends. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2478–2483, 2003