FTIR equivalent weight determination of perfluorosulfonate polymers

Fourier transform infrared (FTIR) and attenuated total reflectance (ATR) spectroscopy studies of the sulfonyl fluoride, potassium salt, and sulfonic acid forms of long and short side chain perfluorosulfonate polymers revealed bands indicative of the sidegroup and backbone compositions, endgroups on the main chain, water content, monomer concentration, and degree of salt hydrolysis. The equivalent weight (EW) of the polymer was obtained by titration and NMR measurements which were then calibrated to either the C F/C O C absorbance band ratio for thin (<1.1 mil) films or to a C F/SO₂F absorbance band ratio for thick films (5 to 25 mils). An FTIR measurement of the film thickness based on the C F group concentration was found to be both a function of the actual thickness and the EW; a method for compensating for this EW dependence is described. Esterification and fluorination of the polymers yielded FTIR measurements of the endgroup compositions on the polymer backbone which were shown to consist of  COF,  COOH,  CO₂CH₃, and  CFCF₂ groups. Thermogravimetric Analysis Infrared (TGA‐IR) spectroscopy of the acid form polymers indicates that degradation begins by the decomposition of the  SO₃H group at 320°C followed by bulk deterioration above 400°C. The FTIR techniques detailed herein have been developed for accurate, reproducible, and rapid compositional measurements of Nafion® and other perfluorosulfonate polymers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Plasma treatment of polymethyl methacrylate to improve surface hydrophilicity and antifouling performance

Surface modification of polymethyl methacrylate (PMMA) by O₂/CF₄ plasma is investigated to improve hydrophilicity and antifouling performance of PMMA. The PMMA surface before and after treatment is characterized by atomic force microscopy, contact angle measurement, and X-ray photoelectron spectroscopy. Antifouling properties are evaluated by protein adsorption and bacterial adhesion experiments using Staphylococcus aureus in vitro. Higher O₂ content in the mixture gas promotes hydrophilicity of the plasma-treated PMMA, while a hydrophobic surface forms at higher CF₄ content. Modifying PMMA improves antifouling performance regardless of the O₂/CF₄ volume ratio, and this improvement increases with rising CF₄ content in O₂/CF₄ plasma working gas. Functional groups C O and C F are detected in O₂/CF₄ plasma-treated PMMA surface and the ratio of C O to C F can be controlled by the O₂/CF₄ volume ratio in the plasma working gas.     

Synthesis of fluorinated polypropylene using CuAAC click chemistry

Synthesis of fluorine containing polypropylene (PP F) from chlorinated polypropylene (PP Cl) via Cu(I) catalyzed Huisgen type 1,3-dipolar cycloaddition (CuAAC) and its water repellency properties are demonstrated. Initially, clickable azido-functional polypropylene (PP N₃) and alkyne-functionalized fluorine compound (F Al) are independently prepared by nucleophilic substitution of PP Cl with azidotrimethylsilane-tetrabutylammonium fluoride and esterification reactions of 2,2,3,3,4,4,5,5-octafluoro-1-pentanol with 4-pentyonic acid. The CuAAC reaction between PP N₃ and F Al leads to corresponding PP F under mild conditions. The chemical structures and surface properties of desired PP F are characterized by Fourier transform infrared, ¹H-NMR, differential scanning calorimetry, scanning electron microscopy, atomic force microscope, and contact angle analyses. Based on water contact angle (WCA) measurement, it is found that both PP Cl and PP N₃ films have shown similar hydrophobicity, whereas the WCA of PP F is surprisingly decreased due to the presence of ester and triazole groups coming from F Al compound and the clicked product. This facile modification procedure could be utilized in order to alter the wetting or thermal properties of the commercial polymers for potential applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47072.     

Synthesis of silane-modified polyphosphate esters and its application in transparent flame-retardant coatings

Polyphosphate ester (PPAE) made from poly(phosphoric acid), pentaerythritol, and 1,3-butylene glycol has been synthesized. The PPAE reacted with dimethyldichlorosilane (DMDCS) to improve its thermal stability and flame retardancy. Four silane-modified polyphosphate esters (SiPPAEs) were obtained. FTIR, ³¹P NMR, and ²⁹Si NMR results showed that the Si Cl bond of DMDCS could react with the C OH and P OH bonds of PPAE, producing Si O C and P O Si bond in SiPPAEs. Different transparent coatings were obtained by mixing the PPAE and SiPPAEs with amino resin. The results of TGA showed that the stability of SiPPAEs was higher than that of PPAE. With the increase of silane content, the thermal stability of the coating increased. As the silane content increased within a certain range, the fire resistance and expansion coefficient increased. But too high silane content had adverse effects on the expansion and reduced the overall insulation effect. The digital photos and SEM/EDX microphotographs of coatings after combustion showed that silica segments could enriched in the surface to form a hard protective layer to prevent further degradation of the char layer. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47199.     

Effect of cupric ion on thermal degradation of chitosan

The thermal degradation of chitosan and chitosan–cupric ion compounds in nitrogen was studied by thermogravimetry analysis and differential thermal analysis (DTA) in the temperature range 30–600°C. The effect of cupric ion on the thermal degradation behaviors of chitosan was discussed. Fourier transform-infrared (FTIR) and X-ray diffractogram (XRD) analysis were utilized to determine the micro-structure of chitosan–cupric ion compounds. The results show that FTIR absorbance bands of  N H,  C N ,  C O C etc. groups of chitosan are shifted, and XRD peaks of chitosan located at 11.3, 17.8, and 22.8° are gradually absent with increasing weight fraction of cupric ion mixed in chitosan, which show that there are coordinating bonds between chitosan and cupric ion. The results of thermal analysis indicate that the thermal degradation of chitosan and chitosan–cupric ion compounds in nitrogen is a two-stage reaction. The first stage is the deacetylation of the main chain and the cleavage of glycosidic linkages of chitosan, and the second stage is the thermal destruction of pyranose ring of chitosan and the decomposition of residual carbon, in which both are exothermic. The effect of cupric ion on the thermal degradation of chitosan is significant. In the thermal degradation of chitosan–cupric ion compounds, the temperature of initial weight loss (T_st), the temperature of maximal weight loss rate (T_max), that is, the peak temperature on the DTG curve, and the peak temperature (T_p) on the DTA curve decrease, and the reaction activation energy (E_a) varies with increasing weight fraction of cupric ion. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Generation of antifouling layers on stainless steel surfaces by plasma‐enhanced crosslinking of polyethylene glycol

Polyethylene glycol (PEG) structures were deposited onto stainless steel (SS) surfaces by spin coating and argon radio frequency (RF)‐plasma mediated crosslinking. Electron spectroscopy for chemical analysis (ESCA) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR‐FTIR) indicated the presence of  CH₂ CH₂ O structure and C C C linkage, as a result of the plasma crosslinking, on PEG‐modified SS surfaces. Scanning electron microscopy (SEM) indicated complete deposition, and water contact angle analysis revealed higher hydrophilicity on PEG‐modified surfaces compared to unmodified SS surfaces. Surface morphology and roughness analysis by atomic force microscopy (AFM) revealed smoother SS surfaces after PEG modification. The evaluation of antifouling ability of the PEG‐modified SS surfaces was carried out. Compared to the unmodified SS, PEG‐modified surfaces showed about 81–96% decrease in Listeria monocytogenes attachment and biofilm formation (p < 0.05). This cold plasma mediated PEG crosslinking provided a promising technique to reduce bacterial contamination on surfaces encountered in food‐processing environments. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 485–497, 2005     

Characterization of ACS modified epoxy resin composites with fly ash and cenospheres as fillers: Mechanical and microstructural properties

Composites of diglycidyl ether of bisphenol A resin modified with Amine Containing Silicone as matrix and fly ash and cenospheres as fillers have been examined for their mechanical and microstructural properties. The microstructural features of the composites in terms of free volume size and content, and its influence on the mechanical properties has been investigated. The results indicate that amine containing silicones works as a good coupling agent between the filler and the resin. Composites with 5 phr fly ash and 30 phr cenospheres showed improved thermal stability as indicated by the increased T_g of the composites, possibly because of increased Si O Si linkages. The tensile strength of cenospheres‐filled composites showed good improvement compared with that of the fly ash‐filled composites. Low density (0.6 g/cc) and higher silica content (60%) of cenospheres seems to be the reason for this observation, which is well corroborated by the free volume data. POLYM. COMPOS., 2011. © 2010 Society of Plastics Engineers     

Infrared spectroscopy evidence for the hydrosilylation of rubbers and hydrogen-containing polysiloxane via heat processing

The hydrosilylation reaction is very important in silicone-introducing reactions and in the crosslinking of silicone rubbers. In this study, through Fourier transform infrared spectroscopy, the hydrosilylation reaction between hydrogen-containing polysiloxane (H-PDMS) and several kinds of rubber, including styrene–butadiene rubber (SBR), nitrile–butadiene rubber (NBR), chloroprene rubber (CR), and natural rubber (NR), with heat processing was researched. The IR spectra of each compound film were determined after reaction with H-PDMS under 110°C for different times. Through the quantitative estimation of the progress of the hydrosilylation reaction in the course of the heat processing, we established a method for calculating the changes of the peak areas of the Si H bond and vinyl groups of each sample at each reaction time and computed the ratio of the integral area of Si H and CC to that of each compound. The Si H content decreased 85 and 30% in SBR–Si and NBR–Si, respectively. However, the ratio of the integral area of transmittance of Si H in NR–Si and CR–Si changed very little during the whole process. The Si H content decreased less than 20% in NR–Si and CR–Si. All ratios of the integral area of transmittance of the vinyl groups (R_Vinyl) of each compound decreased as the reaction time increased at 110°C; the decrease values were very small. The rates of all R_Vinyl decreases were slow, and the decreasing sequence was the same as the order of decreasing Si H content. The hydrosilylation reaction between H-PDMS and SBR was quite smooth in the heat processing and better than that between H-PDMS and NBR. The hydrosilylation reactions of H-PDMS with NR and CR were less satisfying. The results show that polyolefin rubbers can be modified or crosslinked by H-PDMS via heat processing. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Thermally stable poly(propylene carbonate) synthesized by copolymerizing with bulky naphthalene containing monomer

To enhance the thermal and mechanical properties of poly(propylene carbonate) (PPC), the terpolymers were synthesized from carbon dioxide, propylene oxide, and a third monomer, [(2‐naphthyloxy)methyl]oxirane (NMO) using supported zinc glutarate as catalyst. The structure of these terpolymers was confirmed by ¹H NMR spectroscopy. The catalytic activity, molecular weight, carbonate unit content, as well as thermal and mechanical properties were investigated extensively. The experimental results showed that the catalytic activity, molecular weight, and carbonate unit content decreased with the incorporation of NMO. DSC measurements indicated that the introduction of NMO increased the glass transition temperature from 38 to 42°C. TGA tests revealed that the thermal decomposition temperature (T_g?5%) of the synthesized terpolymer increased significantly, being 34°C higher than that of pure PPC. Accordingly, the mechanical properties proved also to be enhanced greatly as evidenced by tensile tests. These thermal and mechanical improvements are of importance for the practical process and application of PPC. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Biodegradable thermoplastic elastomer comprising PLLCA and CaCO<Subscript>3</Subscript> whiskers: mechanical properties,thermal stability and shape memory properties

A biodegradable and thermoplastic elastomer—poly(L-lactide-co-ε-caprolactone) (PLLCA)—was reinforced with 5, 10, 20, and 30 wt% of CaCO₃ whiskers. We assessed the influence of the CaCO₃ whisker content on the mechanical and thermal properties of the PLLCA/CaCO₃ whisker composites. Scanning electron microscopy (SEM) revealed that the CaCO₃ whiskers were uniformly distributed in the composite matrices. The results of differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) showed that the glass transition temperatures (T _g) of the composites increased slightly with increasing CaCO₃ whisker content. At low CaCO₃ whisker contents, the tensile strengths of the composites increased sharply with increasing CaCO₃ content, the Young’s moduli also increased, and the elongation at break values gradually decreased. Thermogravimetric analysis (TGA) showed that the CaCO₃ whiskers can promote the thermal degradation of PLLCA. Shape memory test results indicated that an appropriate amount of CaCO₃ whiskers can improve the shape memory properties of PLLCA.     

One‐step synthesis of graphene nanoplatelets/SiO2 hybrid materials with excellent toughening performance

Graphene nanoplatelets (GNPs)/SiO₂ hybrid materials had been prepared successfully via chemical grafting in one step. Herein, SiO₂ particles and GNPs were connected by poly acryloyl chloride (PACl). The results from Fourier transform infrared spectroscopy showed that functionalized GNPs and SiO₂ particles had been successfully bridged with chemical bonds like O CO and Si O C. And the nanostructure of hybrid materials was characterized by scanning electron microscopy and transmission electron microscopy. All the images indicated that SiO₂ particles were grafted on the surface of GNPs successfully. Moreover, the result of Raman spectroscopy showed that carbon atoms of GNPs became much more disorder, due to destroying the carbon domains during the process of chemical drafting. Meaningfully, the results from tensile tests indicated that Graphene/SiO₂ hybrid materials had better toughening effect on epoxy composites than graphene oxide and SiO₂ particles. POLYM. COMPOS., 36:907–912, 2015. © 2014 Society of Plastics Engineers     

Comparison of thermoset soy protein resin toughening by natural rubber and epoxidized natural rubber

Fully bio‐based soy protein isolate (SPI) resins were toughened using natural rubber (NR) and epoxidized natural rubber (ENR). Resin compositions containing up to 30 wt % NR or ENR were prepared and characterized for their physical, chemical and mechanical properties. Crosslinking between SPI and ENR was confirmed using ¹H‐NMR and ATR‐FTIR. All SPI/NR resins exhibited two distinctive drops in their modulus at glass transition temperature (T_g ) and degradation temperature (T_d ) at around ?50 and 215 °C, corresponding to major segmental motions of NR and SPI, respectively. SPI/ENR resins showed similar T_g and T_d transitions at slightly higher temperatures. For SPI/ENR specimens the increase in ENR content from 0 to 30 wt % showed major increase in T_g from ?23 to 13 °C as a result of crosslinking between SPI and ENR. The increase in ENR content from 0 to 30 wt % increased the fracture toughness from 0.13 to 1.02 MPa with minimum loss of tensile properties. The results indicated that ENR was not only more effective in toughening SPI than NR but the tensile properties of SPI/ENR were also significantly higher than the corresponding compositions of SPI/NR. SPI/ENR green resin with higher toughness could be used as fully biodegradable thermoset resin in many applications including green composites. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44665.     

聚乳酸／醋酸淀粉共混物性能形态研究

采用双螺杆挤出机制备聚乳酸（PLA）／醋酸淀粉（AS）复合材料,研究不同螺杆结构和加工次数对复合材料流变-性能-形态的影响。测试结果表明：通过螺杆Ⅱ、二次挤出后的复合材料的力学性能最优,As含量为60％的复合材料拉伸强度达到27．91MPa。动态流变和SEM的结果表明采用螺杆Ⅱ可以提高PLA与As的共混效果。本文也考察了AS含量对复合材料的力学性能和动态流变性能的影响,结果表明当AS质量含量从45％提高到70％时,复合材料的拉伸强度从36．7MPa降低到16．4MPa;其复数黏度和储能模量则随着AS含量的增加而增加。     

Effect of fiber surface treatment on mechanical,interfacial, and moisture absorption properties of cattail fiber-reinforced composites

Surface treatment of cattail, a lignocellulosic renewable fiber, was investigated to determine the conditions that would reduce moisture absorption while maximizing the properties of cattail fiber-reinforced unsaturated polyester composites. Surface modification of cattail fiber was studied by treating them with 2.5, 5, and 10% of 1,6-diisocyanatohexane (DIH) and 2-hydroxyethyl acrylate (HEA) for three different immersion times (10, 20, and 30 min). DIH-HEA treated fibers were preformed into a non-woven mat and impregnated with unsaturated polyester resin to manufacture composite. The existence of covalent bonds on the treated fibers via N H and C N groups was confirmed by FTIR spectroscopy. The 10% DIH-HEA resulted in the best results; while the mean diameter of the treated fiber decreased by ~37%, the modulus and the strength of it increased by ~267 and ~151%, respectively. Equilibrium moisture regain of the treated fibers and their composites decreased by ~43% and ~40%, respectively. The tensile modulus of the composites increased by ~171%. Enhancement in tensile strength is observed but could not be quantified due to the difference in V_f and scatter in the data. SEM examination confirmed the enhancement in fiber–matrix bonding due to surface treatment.     

Preparation and Characterization of Bioblends from Gelatin and Linear Low Density Polyethylene (LLDPE) by Extrusion Method

Abstract

Bioblends are composites of at least one biodegradable polymer with a non-biodegradable polymer. Successful development of bioblends requires that the biodegradable polymers be compatible with other component biodegradable/synthetic (non-biodegradable) polymers. Bioblends from LLDPE and gelatin were prepared by extrusion and hydraulic heat press technique. The gelatin content in the bioblends was varied from 5 to 20 wt%. Various physico-mechanical properties such as tensile, bending, impact strength (IS), thermal ageing and soil degradation properties of the LLDPE/gelatin bioblends with different gelatin contents were evaluated. The effect of thermal ageing on mechanical properties was studied. The mechanical properties such as tensile modulus (TM), bending strength (BS), bending modulus (BM) were found to increase with increasing gelatin content up to 20 wt%, however tensile strength (TS) and elongation at break (%E _b) were decreased with increasing gelatin content. Impact strength value increased with increasing gelatin content up to 10 wt% and then decreased slightly with increasing gelatin content. The blend containing 20 wt% gelatin showed relatively better mechanical properties than other blends. The values of TS, TM,%E _b, BS, BM and IS for the bioblend with 20 wt% gelatin content are 5.9MPa, 206.3MPa, 242.6%, 12.1MPa, 8 MPa and 13.7 J/cm², respectively. Water uptake increases with increasing soaking time in water and weight loss due to soil burial also increases with increasing gelatin content in the blends but both are significantly lower than that of pure gelatin sheet. Weight loss values after thermal ageing increase with time, temperature and increasing gelatin content in the blend but are much lower than pure gelatin. Mechanical properties such as TS, TM are increased and %E _b is decreased after thermal ageing at 60°C for 30 min. Consequently, among all of the bioblends prepared in this work the blend having 20% gelatin content yields properties such that it can be used as a semi-biodegradable material.     

Mechanical properties of blocked polyurethane/epoxy interpenetrating polymer networks

The mechanical properties of blocked polyurethane(PU)/epoxy interpenetrating polymer networks (IPNs) were studied by means of their static and damping properties. The studies of static mechanical properties of IPNs are based on tensile properties, flexural properties, hardness, and impact method. Results show that the tensile strength, flexural strength, tensile modulus, flexural modulus, and hardness of IPNs decreased with increase in blocked PU content. The impact strength of IPNs increased with increase in blocked PU content. It shows that the tensile strength, flexural strength, tensile modulus, and flexural modulus of IPNs increased with filler (CaCO₃) content to a maximum value at 5, 10, 20, and 25 phr, respectively, and then decreased. The higher the filler content, the greater the hardness of IPNs and the lower the notched Izod impact strength of IPNs. The glass transition temperatures (T_g) of IPNs were shifted inwardly compared with those of blocked PU and epoxy, which indicated that the blocked PU/epoxy IPNs showed excellent compatibility. Meanwhile, the T_g was shifted to a higher temperature with increasing filler (CaCO₃) content. The dynamic storage modulus (E′) of IPNs increased with increase in epoxy and filler content. The higher the blocked PU content, the greater the swelling ratio of IPNs and the lower the density of IPNs. The higher the filler (CaCO₃) content, the greater the density of IPNs, and the lower the swelling ratio of IPNs. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1826–1832, 2006     

Effect of ultraviolet-A radiation on surface structure,thermal, and mechanical and electrical properties of liquid silicone rubber

Liquid silicone rubber (LSR) products outdoors are often subjected to high intensity of ultraviolet (UV)-A radiation. However, the influence of UV-A radiation on LSR is rarely studied. To study the influence of UV-A radiation on LSR, the surface of LSR with UV-A aging time was characterized by tests at different detection depths [X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDS), and Fourier transform infrared spectroscopy (FTIR)]. The operation properties (thermal stability and mechanical and electrical properties) for outdoor insulators were also analyzed. It was found that the porous surface and the loose layer of LSR increased, but the growth rate of them decreased as UV-A aging time increased. SiO₂ fillers were lost in the surface. C H bonds in  CH₃ and  CH₃ in Si CH₃ increased with aging time. The increased crosslinking density increased the thermal stability, hardness, dielectric loss tangent, relative dielectric constant, and volume resistivity and decreased elongation-at-break. The mechanical strength initially increased and then decreased. Based on the proposed aging mechanism, the UV-A resistance of LSR can be improved by reducing the amount of hydrogen-containing silicone oil and by increasing the molecular weight of raw rubber. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47652.     

基体性质对PP／POE共混物力学性能和形态的影响

采用过氧化二异丙苯（DCP）降解PP／POE共混物。熔体流动速率试验结果表明，当DCP含量从0．2‰（质量分数，下同）增加到1‰时，对应的共混物的熔体流动速率从7．0g／10min增加到17．2g／10min，二者基本成线性关系。并且这种增加（相对分子质量的降低）导致其冲击性能从125J／m下降到50J／m；拉伸实验结果表明，共混物相对分子质量的降低对其屈服应力影响不大，这说明相对分子质量的降低主要是引起基体断裂应力的降低，从而导致共混物的冲击强度大大降低；通过扫描电子显微镜观察了不同相对分子质量共混物中橡胶相的分散情况，结果表明，随着DCP含量的增加，共混物中橡胶相的相区尺寸明显增加。因此，共混物冲击强度的降低是基体相对分子质量降低与橡胶相粒径变化共同作用的结果。     

A New Method for Evaluating the Energy Characteristics of C?H?N?O Energetic Compounds

From the law of conversation of energy, the release energy from the initiation to the Chapman–Jouguet point during the detonation of an energetic compound has been deduced as a function of initial density, detonation velocity, and detonation pressure. For C H N O energetic compounds the relative release energy per unit volume (I_v) approaches the relative specific wall kinetic energy (E_cyl/E_HMX) at 19 mm wall displacement from the cylinder test with HMX as reference. A good linear relationship between I_v and E_cyl/E_HMX has been regressed, implying that E_cyl/E_HMX is also a function of initial density, detonation velocity, and detonation pressure. It has been concluded that I_v can reflect the driving force of detonation products of energetic compounds and is appropriate to be used for the evaluation of energy characteristics. The assessment of the energy for a series of synthesized and theoretically designed high‐energy compounds reveals that the future of C H N O energetic compounds is promising after CL‐20 and ONC.     

Synthesis and characterization of terpolymer of N‐cyclohexylmaleimide,methyl methacrylate,and acrylonitrile

Terpolymers of N‐cyclohexylmaleimide, methylmethacrylate, and acrylonitrile (AN) at different AN feed content were synthesized by suspension polymerization. The thermal properties of the terpolymers such as glass transition temperature (T_g) and Vicat softening temperature (T_Vicat) were determined by torsion braid analysis and Vicat softening temperature tester, respectively. The value of T_g and T_Vicat decreased with increasing AN feed content. Thermogravimetric analyses were carried out with the results that the incorporated AN units enhanced the thermal stability of the resulting polymers and a second degradation step appeared with the addition of AN. The mechanical properties (tensile strength and impact strength) of the terpolymers were also detected and the results show that the tensile strength and impact strength of terpolymers increase with increasing AN feed content. The rheological results illustrated that the terpolymers showed rheological behavior similar to that of pseudoplastic liquid. The apparent shear viscosity decreased with the increasing of AN feed content. The flow power index n increased with increasing AN feed content. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 792–796, 2007