Thermal and morphological properties of SA/HPMC blends

Sodium alginate (SA) was blended with varying amounts of hydroxypropyl methylcellulose (HPMC) viz., 10, 20, and 30 wt % by solution casting process. Thus, the obtained blends were characterized by using different analytical techniques such as differential scanning calorimetry (DSC), thermogravimetric analyzer (TGA), Fourier transform infrared spectroscopy (FTIR), and scanning electron microcopy (SEM). FTIR studies reveal the hydrogen bond formation between hydroxyl groups of SA and HPMC polymer chains. DSC analysis shows single glass transition temperature (T_g) for SA/HPMC blends indicating compatibility and physical interaction between SA and HPMC polymer chains. TGA analysis indicates variation of thermal stability of SA with change in compositions of HPMC. SEM studies reveal uniform distribution of second phase in the blends. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Processing and properties of thermoplastic starch and its blends with sodium alginate

Viscosity measurements were carried out on corn starch (CS) and CS–sodium alginate (SA) suspensions at low levels of SA [1 to 10% (w/w)], as a function of temperature. The addition of SA caused the granular CS gelatinization process to occur at a lower onset temperature. CS and CS–SA mixtures were extruded in single‐ and twin‐screw extruders, with 15% glycerol and different water contents. Processing of plasticized CS–SA mixtures required lower temperatures, which is consistent with the viscosity results. Homogeneous and flexible extrudates were obtained by processing in a twin‐screw extruder. Samples in the composition range between 0 and 10% (w/w) SA were examined using tensile tests as a function of water content. Mechanical properties were dependent on the water content and on the SA composition. A significant increase in the Young's modulus value was observed for the blend containing 1% SA. Dynamic mechanical analysis was carried out for CS and CS–SA blends. Two transitions were detected in the temperature range –80 to 150°C. Scanning electron microscopy was used to examine the morphology of the extruded samples. The surfaces of the films were homogeneous, which demonstrated that the CS granules in all samples were characteristically destructured under the conditions used in processing. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 412–420, 2001     

Film processability and properties of polycaprolactone/thermoplastic starch blends

In this work, the processing and properties of blown films prepared from thermoplastic corn starch (TPS) and polycaprolactone (PCL) were studied, in particular at high TPS content. The influence of processing parameters and material moisture content on the tensile properties was also studied. The results show that final film properties are mainly controlled by the draw ratio, blow‐up ratio and PCL concentration in the blends. The results also show that PCL/TPS films are less hydrophilic as PCL content increases. Finally, it was found that a very narrow processing window exists for this blend. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

Sodium alginate/Na+‐rectorite composite films: Preparation,characterization, and properties

Rectorite (REC), one kind of layered silicates, has been applied to polymers to improve their properties. The sodium alginate (SA) layered silicate is a new option to modify the properties of polysaccharides. In this article, SA was modified by Na⁺‐rectorite (Na⁺REC). The chemical structures and microstructures of Na⁺REC and Na⁺REC modified SA (SA/Na⁺REC) were analyzed by using Fourier transform infrared spectrometer and X‐ray diffraction. The morphologies of SA/Na⁺REC composites were observed by using scanning electron microscopy and transmission electron microscopy. The mechanical and anti‐ultraviolet properties as well as thermal properties of SA/Na⁺REC composites were investigated. The results show that the properties of pure SA film can be improved by the addition of Na⁺REC, and SA/Na⁺REC composite containing 2 wt % Na⁺REC has the best intercalation effect and optimum comprehensive properties among the prepared composites in this article. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Compatibilization of polypropylene/polyamide 6 blends using new synthetic nanosized talc fillers: Morphology,thermal, and mechanical properties

New synthetic nanotalc and a commercially available natural fine talc (Luzenac© A3) were chosen in order to establish a comparative study in terms of their contributions on the improvement of the morphology as well as the final properties of PP/PA6 blends prepared by melt processing. At first, the TEM and SEM micrographs showed that both talc particles have a preferential affinity for the more hydrophilic polyamide 6 phase compared with the continuous PP matrix. Moreover, in both cases, the addition of talc fillers induces a significant decrease of the size of the PA6 domains but the better compatibilization efficiency was obtained in the presence of synthetic nanotalc particles. In this work, the positive change induced by the talc nanofillers on the crystallization kinetics and final morphology was highlighted. In addition, compared with natural talc, a highly level of dispersion of talc layers has been obtained with the synthetic nanotalc which is more hydrophilic. Thus, this better dispersion greatly improves the thermal stability of PP/PA6 blends and leads to better mechanical properties (+ 40% in Young's modulus). © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40453.     

Compatibility of polysaccharide/maleic copolymer blends. IV. Thermal behavior of hydroxypropyl cellulose‐containing blends

The compatibility of the hydroxypropyl cellulose (HPC) with maleic acid–vinyl acetate copolymer in the solid state was studied by thermogravimetry, thermo‐optical analysis, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and optical microscopy. It was established that physical interactions are prevalent in blends with a high content of HPC, whereas chemical interactions predominate in blends with a medium and low content of HPC. By increasing the temperature, the thermochemical reactions are favored. Thermal properties are dependent on the mixing ratio of the components. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2585–2597, 2003     

海藻酸钠的流变性及其纤维性能研究

选用黏均分子量分别为1.59×105和3.27×105的海藻酸钠(A)和海藻酸钠(B),用旋转黏度计研究了两种海藻酸钠溶液的流变性,用热重分析(TGA)、扫描电子显微镜(SEM)研究了海藻纤维的热性能及形态结构。结果表明:海藻酸钠溶液的流变行为具有一般非牛顿流体的基本特征;随剪切速率的增加,溶液黏度下降;温度升高,溶液黏度下降,溶液的非牛顿指数、黏流活化能、结构黏度指数(η)都发生变化;海藻酸钠B的η比海藻酸钠A的较低,可纺性较好;海藻纤维具有良好的热稳定性,其表面具有沟槽结构,较好的吸湿性。     

Highly filled blends of a vinylic copolymer with plasticized lignin: Thermal and mechanical properties

The objective of this study was the development of new vinyl flooring formulations with increased resistance to attack by fungi and microorganisms, formulated with plasticizers having chemical compositions different from that of common dioctyl phthalate (DOP). Alkyl phthalate plasticizers are considered to be toxicological and ecotoxicological hazards, although this is still under debate. It is suspected that during the service life of poly(vinyl chloride) (PVC) flooring, the attack of fungi and microorganisms leads to the degradation of DOP and the release of some volatile organic compounds. For this reason, in the new flooring formulations, the vinyl chloride/vinyl acetate copolymer (VC–VAc) was partially replaced with lignin, a natural polymer and a major component of wood and vascular plants. Besides its other functions in wood, lignin imparts resistance to microorganisms. An organosolv lignin from Alcell Technologies, Inc. (AL), was used as a partial replacement of PVC. The influence of the new plasticizers, as well as the influence of the partial replacement of VC–VAc with lignin, on the morphology and thermal and mechanical properties of the composites was investigated with scanning electron microscopy, differential scanning calorimetry, and tensile testing. Butyl benzyl phthalate and diethylene glycol dibenzoate were used as plasticizers; both were compatible with PVC and AL. The results indicated that diethylene glycol dibenzoate was the best plasticizer for these blend composites. In these formulations, AL could replace up to 20 parts of the copolymer. At this level of replacement, the key mechanical properties of the new composites compared very favorably with those of the DOP control formulations. The obtained formulation will be tested further for resistance to fungi and microorganisms. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2000–2010, 2003     

Influence of LiClO4 on the thermal,mechanical, and morphological properties of P(DMS‐co‐EO)/ P(EPI‐co‐EO) blends

The UV‐vis absorption, thermal analysis, ionic conductivity, mechanical properties, and morphology of a blend of poly(dimethylsiloxane‐co‐ethylene oxide) [P(DMS‐co‐EO)] and poly(epichlorohydrin‐co‐ethylene oxide) [P(EPI‐co‐EO)] (P(DMS‐co‐EO)/P(EPI‐co‐EO) ratio of 15/85 wt %) with different concentrations of LiClO₄ were studied. The maximum ionic conductivity (σ = 1.2 × 10^?4 S cm^?1) for the blend was obtained in the presence of 6% wt LiClO₄. The crystalline phase of the blend disappeared with increasing salt concentration, whereas the glass transition temperature (T_g) progressively increased. UV‐vis absorption spectra for the blends with LiClO₄ showed a transparent polymer electrolyte in the visible region. The addition of lithium salt decreased the tensile strength and elongation at break and increased Young's modulus of the blends. Scanning electron microscopy showed separation of the phases between P(DMS‐co‐EO) and P(EPI‐co‐EO), and the presence of LiClO₄ made the blends more susceptible to cracking. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1230–1235, 2004     

Thermomechanical and morphological properties of epoxy blends with hyperbranched polyester: Effect of the pseudo‐generation number

The thermomechanical and morphological properties of some epoxy blends modified with hyperbranched polymers are reported. The effects of pseudo‐generation numbers, from the second to the fourth, were studied. All the hyperbranched polymers used had ? OH end groups. The blends were thoroughly characterized in both the unreacted and cured states. The unreacted blends, characterized by parallel plate rheometry and hot stage microscopy, revealed that pseudo‐generation number can have a profound effect both on the reactivity and the phase separation behavior. Analysis of the cured samples was carried out through scanning electron microscopy, dynamic mechanical tests, and fracture mechanics. The results supported some findings obtained from the analysis of the unreacted blends; and dynamic mechanical analysis helped shed more light on the phase separation behavior. Pseudo‐generation number also influenced the glass transitions of the blends. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Thermal behavior and properties of polystyrene/poly(methyl methacrylate) blends

The thermal behavior and properties of immiscible blends of polystyrene (PS) and poly(methyl methacrylate) (PMMA) with and without PS‐b‐PMMA diblock copolymer at different melt blending times were investigated by use of a differential scanning calorimeter. The weight fraction of PS in the blends ranged from 0.1 to 0.9. From the measured glass transition temperature (T_g) and specific heat increment (ΔC_p) at the T_g, the PMMA appeared to dissolve more in the PS phase than did the PS in the PMMA phase. The addition of a PS‐b‐PMMA diblock copolymer in the PS/PMMA blends slightly promoted the solubility of the PMMA in the PS and increased the interfacial adhesion between PS and PMMA phases during processing. The thermogravimetric analysis (TGA) showed that the presence of the PS‐b‐PMMA diblock copolymer in the PS/PMMA blends afforded protection against thermal degradation and improved their thermal stability. Also, it was found that the PS was more stable against thermal degradation than that of the PMMA over the entire heating range. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 609–620, 2004     

Preparation and properties of halogen‐free flame‐retarded phthalonitrile–epoxy blends

Halogen‐free flame‐retarded blends composed of 2,2‐bis[4‐(3,4‐dicyanophenoxy) phenyl] propane (BAPh) and epoxy resin E‐44 (EP) were successfully prepared with 4,4′‐diaminodiphenyl sulfone as a curing additive. The structure of the copolymers was characterized by Fourier transform infrared spectroscopy, which showed that epoxy groups, a phthalocyanine ring, and a triazine ring existed. The limiting oxygen index values were over 30, and the UL‐94 rating reached V‐0 for the 20 : 80 (w/w) BAPh/EP copolymers. Differential scanning calorimetry and dynamic rheological analysis were employed to study the curing reaction behaviors of the phthalonitrile/epoxy blends. Also, the gelation time was shortened to 3 min when the prepolymerization temperature was 190°C. Thermogravimetric analysis showed that the thermal decomposition of the phthalonitrile/epoxy copolymers significantly improved with increasing BAPh content. The flexible strength of the 20:80 copolymers reached 149.5 MPa, which enhanced by 40 MPa compared to pure EP. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

On the compatibility of polysaccharide/maleic copolymer blends. II. Thermal behavior of pullulan‐containing blends

The compatibility of pullulan with maleic acid/vinyl acetate copolymers in the solid state in the form of thin films was studied with thermogravimetry, differential scanning calorimetry, infrared spectroscopy, and optical microscopy. With respect to morphology, blends with a content of pullulan greater than 85 wt % exhibited an even distribution of finely dispersed particles. The thermal properties were dependent on the mixing ratio, and the interactions between components were quite pronounced in the pullulan‐rich blends. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1782–1791, 2002     

Effects of compatibilizer on the morphological,mechanical, and rheological properties of poly(methyl methacrylate)/poly(N‐methyl methacrylimide) blends

The effects of compatibilizer on the morphological, thermal, mechanical, and rheological properties of poly(methyl methacrylate) (PMMA)/poly(N‐methyl methacrylimide) (PMMI) (70/30) blends were investigated. The compatibilizer used in this study was styrene–acrylonitrile–glycidyl methacrylate (SAN‐GMA) copolymer. Morphological characterization of the PMMA/PMMI (70/30) blend with SAN‐GMA showed a decrease in PMMI droplet size with an increase in SAN‐GMA. The glass‐transition temperature of the PMMA‐rich phase became higher when SAN‐GMA was added up to 5 parts per hundred resin by weight (phr). The flexural and tensile strengths of the PMMA/PMMI (70/30) blend increased with the addition of SAN‐GMA up to 5 phr. The complex viscosity of the PMMA/PMMI (70/30) blends increased when SAN‐GMA was added up to 5 phr, which implies an increase in compatibility between the PMMA and PMMI components. From the weighted relaxation spectrum, which was obtained from the storage modulus and loss modulus, the interfacial tension of the PMMA/PMMI (70/30) blend was calculated using the Palierne emulsion model and the Choi‐Schowalter model. The results of the morphological, thermal, mechanical, and rheological studies and the values of the interfacial tension of the PMMA/PMMI (70/30) blends suggest that the optimum compatibilizer concentration of SAN‐GMA is 5 phr. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43856.     

Intermolecular force and thermal properties of the sulfonyl epoxy blends cured with DGEBA epoxy

The sulfonyl epoxy monomer (SEP) was synthesized and further to blend with the diglycidyl ether of bisphenol A (DGEBA). The glass transition temperature (T_g) of the SEP/DGEBA blended materials increased from 103.7 to 163.8°C. The cross‐linking density and polymer chain self‐association intra‐molecular action affected more than that the polymer–polymer intermolecular action (hydrogen bonding) in the SEP blended with the DGEBA materials. The excess stabilization energy in the overall stabilization was only 0.00145% (14.5 ppm), which indicated that the polymer‐polymer intermolecular action was weak. The thermal degradation of the SEP segments could form various sulfate derivatives at lower temperature and analyzed by the TGA/GC/Mass. The sulfate derivatives could generate the thermal stable chars, which provided the “shielding effect” and antioxidation property. Additionally, these chars could also improve the protective effect and inhibit the thermal‐oxidation decomposition under the air atmosphere. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Thermal properties,structure and morphology of PEEK/thermotropic liquid crystalline polymer blends

The dynamic crystallization and subsequent melting behaviour of poly(aryl ether ether ketone), PEEK, and its blends with a thermotropic liquid crystalline polymer, Vectra^®, have been studied using differential scanning calorimetry, optical microscopy and wide‐angle and small‐angle X‐ray diffraction (WAXS and SAXS) techniques in a wide compositional range. Differences in crystallization rates and crystallinities were related to the structural and morphological characteristics of the blends measured by simultaneous real‐time WAXS and SAXS experiments using synchrotron radiation and optical microscopy. The crystallization process of PEEK in the blends takes place in the presence of the nematic phase of Vectra and leads to the formation of two different crystalline families. The addition of Vectra reduces the crystallization rate of PEEK, depending on composition, and more perfect crystals are formed. An increase in the long period of PEEK during heating was generally observed in the blends at all cooling rates. Copyright © 2003 Society of Chemical Industry     

Polysulphone and poly(phenylene sulphide) blends: 1. Thermal characterization and phase morphology

The phase behaviour and morphology of injection moulded specimens of polysulphone (PSF) and poly(phenylene sulphide) (PPS) blends were studied by differential scanning calorimetry (d.s.c.), dynamical mechanical thermal analysis (d.m.t.a.) and transmission electron microscopy (TEM). The blends are phase separated regardless of the blend composition as revealed by d.s.c., d.m.t.a. and TEM. Upon annealing at 160°C for 2 h, d.m.t.a. results indicate that the PPS phase remains in the amorphous state at compositions <10%. At compositions between 20 and 35%, the PPS appears to be dispersed in a mixed mode of amorphous and crystalline domains. Above 35% the PPS phase appears to become fully crystallized upon annealing of the blends. At 10% PPS, TEM results showed 35–200 nm size dispersion both in the as-moulded and in the annealed specimens. At 20% the PPS phase varied widely in size, from 35 nm to tens of micrometres but remained as an included phase. TEM also revealed a compound morphology of the included phase at a composition of 50 wt% of each component.     

Rubber‐toughened PLA blends with low thermal expansion

In this study, poly (lactic acid) (PLA) blended with various rubber components, i.e., poly (ethylene‐glycidyl methacrylate) (EGMA), maleic anhydride grafted poly(styrene‐ethylene/butylene‐styrene) triblock elastomer (m‐SEBS), and poly(ethylene‐co‐octene) (EOR), was investigated. It was observed that EGMA is highly compatible due to its reaction with PLA. m‐SEBS is less compatible with PLA and EOR is incompatible with PLA. Electron microscopy (SEM and TEM) revealed that a fine co‐continuous microlayer structure is formed in the injection‐molded PLA/EGMA blends. This leads to polymer blends with high toughness and very low linear thermal expansion both in the flow direction and in the transverse direction. The microlayer thickness of rubber in PLA blends was found to play key roles in reducing the linear thermal expansion and achieving high toughness of the blends. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Rheological,morphological, and heat seal properties of linear low density polyethylene and cyclo olefine copolymer (LLDPE/COC) blends

The rheological and morphological properties of linear low‐density polyethylene/cyclo olefin copolymer (LLDPE/COC) blends were investigated, as were their peel seal characteristics when heat sealed to films of either polyethylene (PE) or polyethylene terephtalate (PET). Three blend systems, with COC volume percentages of 5, 10, and 15%, were melt blended in a twin‐screw extruder. A partial phase miscibility/compatibility was initially suggested by Cole–Cole and equivalent plots of the dynamic rheological properties and subsequently confirmed by scanning electron microscopy. The investigation of the systems' heat sealing properties pointed out an interesting industrial potential for PET sheets covered with a fine layer of a LLDPE/COC blend before heat sealing to a PE film for packaging applications. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

海藻酸钠的热分解研究

用热重法 ( TG)和差示扫描量热法 ( DSC)并结合 IR详细研究了海藻酸钠的热分解过程。研究表明 ,海藻酸钠的热分解共分四步 :60～ 170°C之间海藻酸钠脱去内部结合水 ;2 2 0～ 2 80°C之间海藻酸钠裂解为中间产物 ;3 0 0～ 3 70°C之间中间产物进一步裂解并部分碳化 ;5 60°C左右最终氧化生成 Na2 O。并用三步判别法对人们较感兴趣的第二步反应的机理和动力学进行了研究。