木质素磺酸钠与PVA共混薄膜的制备与表征

以木质素磺酸钠(LS)和聚乙烯醇(PVA)为主要原料,添加适量硼砂、明胶在水溶液中溶解共混,流延成膜.通过单因素和正交实验优选了LS/PVA共混膜制备的条件,对共混膜进行了耐水性、形貌、红外、热重、X射线衍射及差示扫描量热分析.结果表明:影响共混膜性能的主要因素有LS含量、硼砂含量以及反应时间,当硼砂含量为2.0%时,...     

Preparation and characterization of poly(vinyl alcohol) and gelatin blend films

Poly(vinyl alcohol) (PVA) is a water-soluble polymer that has been studied intensively because of several interesting physical properties that are useful in technical applications, including biochemical and medical applications. In this article, we report the effects of the addition of gelatin on the optical, microstructural, thermal, and electrical properties of PVA. Pure and PVA/gelatin blend films were prepared with the solution-casting method. These films were further investigated with Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), X-ray diffraction (XRD), ultraviolet–visible (UV–vis) spectroscopy, and dielectric measurements. The FTIR spectrum shows a strong chemical interaction between PVA and gelatin molecules with the formation of new peaks. These peaks are due to the presence of gelatin in the blend films. The DSC results indicate that the addition of gelatin to PVA changes the thermal behavior, such as the melting temperature of PVA, and this shows that the blends are compatible with each other. This also shows that the interaction of gelatin and PVA molecules changes the crystallite parameters and the degree of crystallinity, and this supports the XRD results. The UV–vis optical study also reflects the formation of the complex and its effect on the microstructure of the blend film. Moreover, the addition of gelatin also gives rise to changes in the electrical properties of PVA/gelatin blend films. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Characterization of polyvinyl alcohol/gelatin blend hydrogel films for biomedical applications

In the present investigation, attempt was made to prepare blend hydrogel by esterification of polyvinyl alcohol with gelatin. The blend hydrogel was further converted into films by the conventional solution‐casting method. These films were characterized by FTIR, DSC, and X‐ray diffraction studies. The refractive index and viscosity of different composition of the blends were measured in the solution phase of the material. The mechanical properties of the blend films were measured by tensile test. Swelling behavior of the blend hydrogel was also studied. The FTIR spectrum of the blend film indicated complete esterification of the free carboxylic group of gelatin. The DSC results indicate that the addition of gelatin with PVA changes the thermal behavior like melting temperature of PVA, which may be due to the miscibility of PVA with gelatin. The interaction of gelatin with PVA molecule changes the crystallite parameters and the degree of crystallinity. The crystallinity of the blend film was mainly due to gelatin. The comparison of viscosity indicated an increase in the segment density within the molecular coil. The results revealed the changes observed in the properties of the gel, and it enhances the gel formation at viscoelastic phase of the material. The blend film had sufficient strength and water‐holding capacity. The results obtained indicated that the blend film could be used for various biomedical applications such as wound dressing and drug‐delivery systems. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Study on the properties of nano‐TiO2 particles modified silk fibroin porous films

Using the freeze‐drying method, Nano‐TiO₂/silk fibroin porous films were synthesized with different ratios of TiO₂ to silk fibroin solution. Through scanning electron microscopy (SEM), X‐ray diffraction (XRD), thermogravimetric analysis (TGA), tensile strain, and water‐solubility tests, the structures and properties of these porous films were characterized. The SEM results indicated that the pores of the nano‐TiO₂/silk fibroin porous films were uniformly distributed by the freeze‐drying method. The XRD analysis indicated that the formation of nano‐TiO₂ particles might induce a conformational transition of silk fibroin from the typical Silk I to the typical Silk II structure partly with an increase in the crystallinity of the porous films. Compared with the pure silk fibroin porous films, the mechanical properties of nano‐TiO₂/silk fibroin porous films were improved, and its heat transition temperature was also enhanced; however, the water‐solubility of this material was diminished. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Studies of chitosan. I. Preparation and characterization of chitosan/poly(vinyl alcohol) blend films

Various blending ratios of chitosan/poly (vinyl alcohol) (CS/PVA) blend films were prepared by solution blend method in this study. The thermal properties and chemical structure characterization of the CS/PVA blend films were examined by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), and Fourier transform infrared (FTIR). Based upon the observation on the DSC thermal analysis, the melting point of PVA is decreased when the amount of CS in the blend film is increased. The FTIR absorption characteristic is changed when the amount of CS in the blend film is varied. Results of X‐ray diffraction (XRD) analysis indicate that the intensity of diffraction peak at 19° of PVA becomes lower and broader with increasing the amount of CS in the CS/PVA blend film. This trend illustrates that the existence of CS decreases the crystallinity of PVA. Although both PVA and CS are hydrophilic biodegradable polymers, the results of water contact angle measurement are still shown as high as 68° and 83° for PVA and for CS films, respectively. A minimum water contact angle (56°) was observed when the blend film contains 50 wt % CS. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Preparation and characterization of polyethylene oxide (PEO)/gelatin blend for biomedical application: Effect of gamma radiation

polyethylene oxide (PEO)/gelatin blend membranes of four different compositions (w/w) (5/95, 10/90, 20/80, and 30/70) were prepared by solution casting. The films were irradiated by gamma radiation at a total dose of 250 krad (dose rate of 321 krad/h). The X‐ray diffractograms demonstrate both the PEO and radiation influences on the blend thus enhancing crystallinity of gelatin. X‐ray diffractograms of irradiated blend films containing 30% PEO showed highest integrated intensity. The DTA and TGA study showed that the irradiated blend films are more thermally stable than the non‐irradiated films. TMA study showed that the incorporation of PEO into gelatin increased melting point of the blend films. The melting point for irradiated gelatin film changes from 52.9°C to 75.6°C and the glass point changes from 60.3°C to 90.6°C. The phase separation and compatibility of the PEO/gelatin blend films were studied by scanning electron microscopy (SEM). The experimental results showed that the blend films exhibit higher thermal stability and improved mechanical properties in dry state, which suggests the occurrence of interaction detected by XRD and DTA among gelatin, PEO, and water molecules in the films. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Study on physical properties of blend films from gelatin and polyacrylamide solutions

Blend films of gelatin and polyacrylamide (PAAm) were prepared by casting the mixed aqueous solutions of both samples in different ratios. All blend films obtained are optically clear to the naked eye. The structure and physical properties of the films were studied by FT‐infrared (FTIR), wide‐angle X‐ray diffraction (WAXD), differential thermal analysis (DTA), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The experimental results show that the blend films exhibit the higher thermal stability and improved mechanical properties of both tensile strength and elongation at break in dry states, which suggests the occurrence of interaction detected by FTIR between gelatin, PAAm, and water molecules in the films. The morphological transition of the blend films from gelatin‐like to PAAm‐like was observed by SEM. Furthermore, moisture content and water swelling property of the blend films were also investigated, which was consistent with the results from SEM. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 949–955, 2002     

Structure and physical properties of silk fibroin/polyacrylamide blend films

This article deals with the characterization of blend films obtained by mixing silk fibroin (SF) and polyacrylamide (PAAm). The DSC curves of SF/PAAm blend films showed overlapping of the main thermal transitions characteristic of the individual polymers. The exothermic peak at 218°C, assigned to the β‐sheet crystallization of silk fibroin, slightly shifted to a lower temperature by blending. The weight‐retention properties (TG) of the blend films were intermediate between those of the two constituents. The TMA response was indicative of a higher thermal stability of the blend films, even at low PAAm content (≤25%), the final breaking occurring at about 300°C (100°C higher than pure SF film). The peak of dynamic loss modulus of silk fibroin at 193°C gradually shifted to lower temperature in the blend films, suggesting an enhancement of the molecular motion of the fibroin chains induced by the presence of PAAm. Changes in the NH stretching region of silk fibroin were detected by FTIR analysis of blend films. These are attributable to disturbance of the hydrogen bond pattern of silk fibroin and formation of new hydrogen bonds with PAAm. The values of strength and elongation at break of blend films slightly improved at 20–25% PAAm content. A sea–island structure was observed by examining the air surface of the blend films by scanning electron microscopy. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1563–1571, 1999     

Mechanical and barrier properties of edible starch–protein‐based films

The present investigation dealt with the mechanical properties, water‐vapor transmission behavior at different relative humidity conditions, and DSC thermograms of edible films formulated using various proteins (casein, gelatin, albumin) in combination with starch and nonthermal as well as intense thermal blending. Nonthermal blended film showed in the DSC thermogram a double T_g, indicating poor miscibility of the components and, hence, a poor film‐forming property. However, the DSC thermogram of all the films based on intense thermal blending showed a single T_g, indicating the complete molecular miscibility of the components. Casein‐based film showed a lower water‐vapor transmission rate, water gain at different relative humidity conditions, and higher tensile strength compared to its counterparts containing gelatin and albumin. Since the casein–starch blend gave better film properties, a blend of hydrophobic carnauba wax and casein was prepared to compare the properties of hydrophilic–hydrophilic and hydrophobic–hydrophilic blends. Both these blends compared well with respect to the water‐vapor transmission rate. Wax‐based film showed multiphased behavior in the DSC thermograms and the percent elongation was lower as compared to the casein–starch blend. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 64–71, 2003     

PPC/PDAP共混膜的制备和性能

将过氧化二异丙苯(DCP)置于特定温度下,引发邻苯二甲酸二烯丙酯(DAP)在聚碳酸亚丙酯(PPC)溶液中聚合,制备得到聚碳酸亚丙酯/聚邻苯二甲酸二烯丙酯(PPC/PDAP)共混膜。采用红外光谱仪(FTIR)、X射线衍射仪(XRD)、差示扫描量热仪(DSC)、热重分析仪(TGA)、万能试验机和水蒸气透过率测试仪对共混膜的红外吸收、结晶性、热、力学和阻隔性能进行了表征。结果表明,通过DAP的聚合,提高了PPC的结晶性,使PDAP在PPC基体中形成交联网络,提高了共混膜的热、力学和阻隔性能。相比纯PPC,当DAP含量为20%时,共混膜的玻璃化转变温度和拉伸强度分别提高了5.3℃和266%;当DAP含量为40%时,共混膜的失重5%热分解温度提高了50.9℃,透湿系数下降了25%,因此,阻隔性能得到了提升。     

Biodegradable blend films based on two polysaccharide derivatives and their use as ibuprofen‐releasing matrices

Differential scanning calorimetry (DSC), FTIR, X‐ray diffraction (XRD), and viscosity methods were used to examine the miscibility, interaction, and degradability of cationic guar gum (GG) and sodium carboxymethylcellulose (NaCMC) in their blend films. The experiment results prove that there exist electrostatic interactions and hydrogen bonding between GG and NaCMC. Blend films degrade quicker than pure GG or NaCMC film. Furthermore, the degradation rate of blend films is related to the interactions between GG and NaCMC. Based on the research of blend films as the drug carriers for Ibuprofen, it is found that the blend composition, initial drug concentration, and pH value affect the drug release and the GG/NaCMC blend films have good sustained release performance. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3553–3559, 2007     

Thermotropic liquid crystallinity,thermal decomposition behavior,and aggregated structure of poly(propylene carbonate)/ethyl cellulose blends

Maleic anhydride end capped poly(propylene carbonate) (PPC‐MA) was blended with ethyl cellulose (EC) by casting from dichloromethane solutions. The thermotropic liquid crystallinity, thermal decomposition behavior, and aggregated structure were investigated by differential scanning calorimetry (DSC), thermogravimetry (TGA), and wide angle X‐ray diffraction (WAXD). DSC exhibits thermotropic liquid crystallinity in the rich EC composition range. TGA shows that thermal decomposition temperatures were elevated upon interfusing EC into PPC‐MA. WAXD corroborates that EC and PPC‐MA/EC blend films cast from dilute dichloromethane solution possessed cholesteric liquid crystalline structure in the rich EC composition range, and that dilution of PPC‐MA with EC increased the dimension of noncrystalline region, leading to a more ordered packed structure. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 584–592, 2006     

Characterization of gamma irradiated concentrated aqueous solutions of chitosan/sodium alginate blends and their drug uptake‐release characters

Blends films based on different ratios of concentrated aqueous solutions of chitosan (CS) and sodium alginate (AG) in the presence of 1% of glutaraldehyde, as a cross‐linking agent for chitosan, were prepared by solution casting and then exposed to gamma irradiation. The formed blends were characterized by IR spectroscopic analysis, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The uptake‐release properties of CS/AG blends, taking ketoprofen as an example for drug, were also investigated. DSC thermograms of CS/AG blends revealed good miscibility was sustained between CS and AG. The water uptake and gel content of CS/AG blends was found to decrease by increasing the ratio of AG in the initial solution. The IR spectra indicated the formation of cross‐linking and hydrogen bonding, while the TGA study showed that the CS/AG blends displayed higher thermal stability than pure CS polymer. Based on Fick's law, it was demonstrated that the main parameters affecting the release of ketoprofen drug from the CS/AG blend hydrogels were composition and pH. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Study on antibacterial O-carboxymethylated chitosan/cellulose blend film from LiCl/N, N-dimethylacetamide solution

Two types of O-carboxymethylated chitosan (O-CMCh)/cellulose polyblends were prepared by mixing cellulose LiCl/N,N-dimethylacetamide (DMAc) solution with O-CMCh aqueous solution (I) or DMAc emulsion (II) and their corresponding films (I and II) were regenerated in water. The (O-CMCh)/cellulose films obtained were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and wide-angle X-ray-scattering (WAXS). FTIR analyses showed that amino groups of O-CMCh were not affected during the film formation. SEM observations indicated that the O-CMCh/cellulose polyblend displayed a heterogeneous microstructure. O-CMCh microdomains dispersed in the cellulose matrix of the blend film. Blend film I showed a better dispersion of the O-CMCh microdomains than blend film II did. DSC and WAXS analyses suggested that, for both two kinds of the blend films, the addition of O-CMCh did not significantly influence the crystallinity and thermal properties of cellulose. The antibacterial activity of the films against Escherichia coli (E. coli) was also measured via optical density method. Both blend films I and II exhibited satisfying antibacterial activity against E. coli, even the O-CMCh concentration was only 2 wt%. Due to the coagulation effect of water on the polyblend, O-CMCh water solution is suitable for the preparation of the blend film with low O-CMCh concentration, while O-CMCh DMAc emulsion should be selected when high O-CMCh concentration is needed.     

壳聚糖/聚乙烯醇共混膜的氢键和相容性

采用溶液共混法制备了不同配比的壳聚糖/聚乙烯醇共混膜,通过变温FTIR、TG、DTA、DSC及XRD等对共混膜的结构、氢键相互作用、热行为和结晶性等进行研究。实验结果表明,共混膜中壳聚糖与聚乙烯醇间存在强烈的氢键相互作用。氢键的存在使壳聚糖的热稳定性提高,聚乙烯醇结晶性下降,促进壳聚糖与聚乙烯醇相容。当壳聚糖/聚乙烯醇共混膜的质量比分别为10/0、7/3、5/5、3/7和0/10时,共混膜的初始分解温度分别为244 ℃、257 ℃、260 ℃、262 ℃和285 ℃。聚乙烯醇熔融温度从193 ℃下降到173 ℃,玻璃化转变温度从74.2 ℃上升至80 ℃,结晶度Xc从3.57%下降到1.97%。     

Synthesis and characterization of cationic gemini surfactant modified Na–bentonite and its applications for rubber nanocomposites

A cationic gemini surfactant (N‐isopropyl‐N , N‐dimethyldodecan 1‐aminium bromide) was synthesized by quaternization reaction. The synthesized surfactant was characterized by Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (1H NMR) spectroscopy. Modified Na–bentonite (organoclay) was obtained by the intercalation of a gemini surfactant between the layers of sodium bentonite and characterized by X‐ray diffraction (XRD), transmission electron microscopy (TEM), FTIR, thermogravimetry–differential thermal analysis (TGA–DTA) and differential scanning calorimetry (DSC) techniques. The results of XRD, TEM, FTIR, TGA, and corresponding DSC analysis indicate that gemini surfactant has been successfully intercalated into the clay layers. Rubber‐based nanocomposites have been prepared by incorporating various concentration of organically modified bentonite on to natural rubber/styrene–butadiene rubber (NR/SBR) rubber blend (75/25) using two roll mill. Effect of organoclay content on XRD, curing, mechanical, and scanning electron microscopy (SEM) properties of the nanocomposites are investigated. The morphological study showed the intercalation of nanoclay in NR/SBR blend chain. It was found that the organoclay decrease the optimum and scorch time of the curing reaction, increase maximum torque and the curing rate, which was attributed to the further intercalation during vulcanization process. Mechanical properties such as tensile strength, modulus and elongation at break have improved. POLYM. COMPOS., 38:396–403, 2017. © 2015 Society of Plastics Engineers     

Microscopic Fourier transform infrared/differential scanning calorimetry system used to study the different thermal behaviors of polymethacrylate copolymers of eudragits RS,RL, E 30D,or E

The thermal stability of Eudragits RL, RS, E 30D, and E films was qualitatively investigated by the reflectance Fourier transform infrared microspectroscopy equipped with differential scanning calorimetry (FTIR/DSC microscopic system). DSC and thermogravimetric analysis (TGA) were also used to study the thermal behavior of the granules of the raw material and the film of these polymers. The results indicate that the Eudragit RL, RS, or E 30D polymer exhibited a higher thermal‐stable behavior, but Eudragit E easily formed the six‐membered cyclic anhydride through heating process via the inter‐ or intramolecular ester condensation. The leaving group in Eudragit E molecule was larger than that in Eudragit E 30D, and the leaving group of salt in Eudragit RS or RL was too stable to polycondense. The DSC thermograms and TGA curve also confirmed this result. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 829–835, 2000     

Mechanical and Physical Properties of Cassava Starch-Gelatin Composite Films

The effect of gelatin concentrations on the mechanical properties and solubility of cassava starch-based films containing glycerol was studied. Increasing concentration of gelatin increased tensile strength but reduced elongation at break and water solubility of the composite films. Films containing 30% gelatin showed the highest tensile strength. Fourier transform infrared spectroscopy (FT-IR) spectra indicated intermolecular interactions between cassava starch and gelatin in composite films. The X-ray diffraction (XRD) technique demonstrated pseudo-crystalline regions in the cassava starch-gelatin composite films, and it is supposed that the interactions between cassava starch and gelatin were shown in the diffractograms by shifts in scattering angles. The differential scanning calorimetry (DSC) thermograms and scanning electron microscopy (SEM) micrographs confirmed homogeneity of cassava starch-gelatin films. Cassava starch-gelatin composite films have the potential to replace conventional packaging, and the films developed in this work are suggested to be suitable for low-moisture food and pharmaceutical products.     

Morphology,thermal, and crystallization properties of poly(butylene succinate)‐grafted Nanocrystalline Cellulose by polymerization in situ

The compounds 1,4‐butanediol, succinic anhydride, and nanocellulose (NCC) were used to synthesize poly(butylene succinate)‐grafted Nanocrystalline Cellulose (PBS‐g‐NCC) nanocomposites via polymerization in situ. The resulting structures were examined by transmission electron microscopic (TEM), scanning electron microscope (SEM), ¹H and ¹³C‐nuclear magnetic resonance spectroscopic (NMR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and X‐ray diffraction (XRD) analyses. TEM showed the cellulose to be nanoscale and SEM analysis indicated that 3 wt% NCC dispersed well in PBS matrix. ¹H and ¹³C‐NMR analyses indicated the product to possess peaks characteristic of PBS. DSC analysis clearly showed that the NCC increased the PBS crystallinity when 3 wt% NCC was introduced into PBS matrixes by polymerization in situ, compared to pure PBS. TGA illustrated that the thermal stability of PBS‐g‐NCC was better than that of pure PBS, when 3 wt% NCC was added. XRD analysis suggested that 3 wt% NCC improved PBS crystallinity, which was in good agreement with the present DSC results. POLYM. ENG. SCI., 59:928–934, 2019. © 2018 Society of Plastics Engineers     

Structural,electrical, thermal,and gas sensing properties of new conductive blend nanocomposites based on polypyrrole/phenothiazine/silver‐doped zinc oxide

The main aim of this study is to investigate the effect of silver‐doped zinc oxide (Ag‐ZnO) loading on the structural, morphological, thermal and electrical properties, and gas sensing behavior of polypyrrole (PPy)/phenothiazine (PTZ)‐blend nanocomposites. The composites are characterized by FTIR, XRD, SEM, TEM, DSC, TGA, and impedance studies. FTIR spectra exhibit the presence of Ag‐ZnO in the PPy/PTZ blend. XRD analysis shows that the semicrystalline behavior of the polymer blend is greatly enhanced by the addition of Ag‐doped ZnO particles. Uniform dispersion of nanoparticles in the polymer is obtained from SEM analysis. The TEM images confirm the presence of spherically shaped nanoparticles in PPy/PTZ blend with a size of 10–25 nm. The DSC measurement indicates that the glass transition temperature of PPy/PTZ blend was significantly improved in the presence of Ag‐doped ZnO nanoparticles. The thermal decomposition temperature of nanocomposite obtained from TGA shows an increase with increase in the content of Ag‐ZnO particles. The incorporation of Ag‐doped ZnO nanoparticles to PPy/PTZ blend exhibit increase in the AC conductivity and dielectric properties of the nanocomposite, due to the pilling of charges at the extended interface of the composite system. The DC conductivity of the nanocomposite increases with the loading of nanoparticles. The ammonia gas sensing performance of PPy/PTZ/Ag‐ZnO nanocomposite is analyzed, and the result shows that the fabricated blend composite can be used as a promising candidate for the easy access of gas molecules. J. VINYL ADDIT. TECHNOL., 26:187–195, 2020. © 2019 The Authors. Journal of Vinyl and Additive Technology published by Wiley Periodicals, Inc. on behalf of Society of Plastics Engineers.