bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adsorption and desorption of copper(II) from solutions on new spherical cellulose adsorbent
Authors: Liu Minghua , Deng Yun , Zhan Huaiyu , Zhang Xinshen 
Published: October 2004

AbstractAn investigation was conducted on the adsorption and desorption of copper(II) from aqueous solutions with a new spherical cellulose adsorbent containing the carboxyl anionic group. Various factors affecting the adsorption were optimized. The adsorption of Cu2+ ions on the adsorbent was found to be dependent on the initial time and pH, the concentration, and the temperature. The adsorption process follows both Freundlich and Langmuir adsorption isotherms and was found to be endothermic (ΔH = 23.99 kJ/mol). The Cu2+ ions adsorbed on the adsorbent can be recovered with a NaOH or HCl aqueous solution. The maximum percentage of recovery is about 100% when 2.4 mol/L HCl solution is used. In addition, only 7.2% of the adsorption capacity is lost after 30 replications of the adsorption and desorption. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 478–485, 2002; DOI 10.1002/app.10114
Phase separation, physical properties and melt rheology of a range of variously transesterified amorphous poly(ethylene terephthalate)–poly(ethylene naphthalate) blends
Authors: Becker O. , Simon G. P. , Rieckmann T. , Forsythe J. S. , Rosu R. F. , Völker S. 
Published: October 2004

AbstractAmorphous, partially transesterified poly(ethylene terephthalate)/poly(ethylene naphthalate) (PET/PEN) blends of different levels of transesterification and blend composition were investigated in terms of resultant phase behavior, thermal transitions, and melt rheological properties. Intrinsic viscosities of the lowest transesterified material were found to be significantly below those of a physical blend of an identical composition, but at higher levels of transesterification, there was little difference. This was similarly found in melt rheometry measurements, where the zero‐shear rate viscosity of the low and highly transesterified mixtures were similar. Both solution and melt rheometry indicated that the molecular weight decreased by thermal degradation from processing. This is believed to play an important role in determining the final molecular architecture and properties. For similar levels of ester interchange, there was a minimum observed in zero shear melt viscosity at around 40 wt % PEN. This is likely due to competition between the slightly transesterified copolymer chains having poorer packing in the melt and reduced entanglement. Differential scanning calorimetry and dynamic mechanical thermal analysis were used to investigate the phase behavior of partially and fully transesterified blends. Results for the glass transition of the highly transesterified blends were compared with the theoretical values calculated from the Fox equation and were found to be close, although slightly lower. A correlation between the melting temperature of the blend and the degree of transesterification was shown to exist. This correlation can be used to estimate the degree of ester exchange reaction from these melting transitions. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1556–1567, 2002
Influence of processing time and composition in the microwave absorption of EPDM/PAni blends
Authors: Faez Roselena , Martin Inácio M. , De Paoli Marco‐A , Rezende Mirabel C. 
Published: October 2004

AbstractBlends of ethylene–propylene–diene monomer (EPDM) and polyaniline (PAni) doped with dodecylbenzene sulfonic acid were prepared by mechanical mixing in an internal mixer at various compositions and times. Reflectivity characteristics of the blends in the 8–12‐GHz range were investigated with the Naval Research Laboratory arch method. The microwave absorption behavior was affected by the processing time and blend composition. The correlation of reflectivity measurements with morphology observations made with scanning electron microscopy suggested that the distribution and concentration of the PAni phase within the EPDM matrix altered the wave–matter interactions. The radar‐absorbing materials prepared in this work showed broadband behavior with microwave radiation absorption of up to 90%. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1568–1575, 2002
Thermomechanical properties and morphology of interpenetrating polymer networks of polyurethane–poly(methyl methacrylate)
Authors: Desai Sonal , Thakore I. M. , Brennan Anthony , Devi Surekha 
Published: October 2004

AbstractInterpenetrating networks (IPNs) of polybutadiene‐based polyurethane (PU) and poly(methyl methacrylate) (PMMA) were synthesized. The effect of the incorporation of 2% glycidyl methacrylate (GMA) and 2‐hydroxyethyl methacrylate (2‐HEMA) on the thermal, mechanical, and morphological properties of IPNs was investigated. Both 2‐HEMA and GMA led to improvements in these properties. However, 2‐HEMA‐containing IPNs showed somewhat better tensile strength, elongation, and damping characteristics. The morphology of IPNs containing 2‐HEMA showed better mixing of the components. The improvement in the properties was observed for up to 40% PMMA in the IPNs. Differential scanning calorimetry thermograms showed the presence of three glass transitions. The third glass‐transition temperature was explained by possible grafting of methyl methacrylate onto PU. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1576–1585, 2002
Curing kinetics and thermal property characterization of a bisphenol‐F epoxy resin and DDO system
Authors: Jungang Gao , Deling Li , Shigang Shen , Guodong Liu 
Published: October 2004

AbstractThe curing kinetics of a bisphenol‐F epoxy resin (BPFER)/4,4′‐diaminodiphenyl oxide (DDO) system were studied with isothermal experiments via differential scanning calorimetry. Autocatalytic behavior was shown in the first stages of the cure for the system, which was well described by the model proposed by Kamal that includes two rate constants, k1 and k2, and two reaction orders, m and n. The curing reaction at the later stages was practically diffusion‐controlled because of the onset of gelation and vitrification. For a more precise consideration of the diffusion effect, a diffusion factor, f(α), was introduced into Kamal's equation. In this way, the curing kinetics were predicted well over the entire range of conversion, covering both previtrification and postvitrification stages. The glass‐transition temperatures (Tg's) of the BPFER/DDO system partially isothermally cured were determined by means of torsional braid analysis, and the results showed that Tg's increased with conversion up to a constant value. The highest Tg was 376.3 K. The thermal degradation kinetics of cured BPFER were investigated with thermogravimetric analysis, which revealed two decomposition steps. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1586–1595, 2002
Molecular orientation in the surface layer of polytetrafluorinethylene
Authors: Aleinik A. I. , Saydov G. V. 
Published: October 2004

AbstractAttenuated total reflectance spectroscopy was used to study the orientation and deformation of molecular chains in polymers. Reflection and transmission spectra of the polytetrafluorinethylene (PTFE) films were obtained. Parameters of the macromolecule's degree of order were determined for the whole volume and for the surface layer of uniaxially orientated PTFE, and on this basis, we determined the character of dependence lSL(L), where lSL is the effective thickness of the surface layer and L is the film stretching degree. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1596–1599, 2002
Polymers from renewable resources: Kinetics studies of the radiochemical graft copolymerization of styrene onto cellulose extracted from pine needles and the effect of some additives on the grafting parameters in an aqueous medium
Authors: Chauhan Ghanshyam S. , Dhiman Surya K. , Guleria Lalit K. , Kaur Inderjeet 
Published: October 2004

AbstractIn an attempt to develop an alternative to petro‐based polymers, we graft‐copolymerized cellulose isolated from the needles of Pinus roxburghii with styrene in a limited aqueous medium in air by simultaneous irradiation using gamma rays as the initiator. The optimum conditions for obtaining maximum grafting were determined as a function of monomer concentration, total dose of irradiation, and amount of water. Maximum percentage of grafting (Pg; 79.9) was obtained at a total dose of 1.152 × 104 Gy with 1.325 × 10−4 mol of styrene. The effect of methanol, LiNO3, Cu(NO3)2, Mohr's salt, H2SO4, HNO3, and AcOH on Pg was studied. All the additives were found to decrease graft yield, contrary to some reported studies. Total percentage conversion and rates of polymerization, grafting, and homopolymerization were evaluated. Evidence of grafting was provided by the characterization of cellulose and its graft copolymers by Fourier transform infrared spectroscopy, thermogravimetry, and observation of the swelling behavior in some solvents. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1490–1500, 2002
Enhancement of the mechanical properties and interfacial interaction of a novel chitin‐fiber‐reinforced poly(ϵ‐caprolactone) composite by irradiation treatment
Authors: Yang Anle , Wu Renjie 
Published: October 2004

AbstractThe effects of the fiber reinforcement of a novel bioabsorbable chitin‐fiber‐reinforced poly(ϵ‐caprolactone) (PCL) composite were improved by irradiation treatment. The tensile strength and tensile modulus of the treated specimens were enhanced with respect to those of the untreated specimens. An increase in the fiber content (Cf) resulted in an increase in this enhancement tendency until Cf was 45%. A further increase in Cf increased the tensile modulus but decreased the strength. The flexural strength and flexural modulus were increased for the irradiation‐treated specimens in the same way as the tensile test. The microstructure of the tensile fracture showed an improvement in interfacial bonding for the irradiated specimens. The glass‐transition temperature (Tg) of the composite increased with an increase in Cf for the irradiation‐treated specimens, but there was no change in Tg for the untreated specimens with various values of Cf. This indicated that, for the composites with irradiation treatment, the fiber intensively affected the molecular segmental motion of PCL and thereby enhanced the interfacial interaction between the matrices and fibers. The same slope of the storage modulus (G′) versus the loss modulus (G″) for the irradiated specimens suggested an increase in the compatibility of the composite in comparison with the decrease in the slope with increasing Cf for the untreated specimens. All this demonstrated that there was some interfacial reaction between the fiber and matrix that resulted in the presence of an interfacial phase and improved the mechanical properties of the materials. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 486–492, 2002; DOI 10.1002/app.10149
Fracture and impact properties of modified nylon 11
Authors: Li Qi Fang , Tian Ming , Kim Dong Gil , Wu De Zhen , Jin Ri Guang 
Published: October 2004

AbstractSupertough nylon 11 is prepared by using a plasticizer. The influence of plasticizers on the impact property and tensile properties of plasticized nylon 11 were investigated. The results show that the impact strength is improved remarkably by methylbenzene sulfonamide, and the tensile strength is almost the same as that of natural‐grade nylon 11. The study of the fracture morphology on plasticized supertough nylon 11 indicates that the fracture surface of plasticized supertough nylon 11 has a special feature, which is different from the fracture surface of general ductile polymer materials. It is similar to that of a multilayer distorted lamellar structure. There are many oriented fibrillar clusters on each layer, which are perpendicular to the impact direction. This was a new breaking phenomenon, which is found on supertough nylon 11. In regard to the experimental results, a “multilayer crack extension” mechanism is put forward. The fracture of supertough nylon 6 also verified this mechanism. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1600–1607, 2002
Morphology of micron‐sized, monodisperse, nonspherical polystyrene/poly(n‐butyl methacrylate) composite particles produced by seeded dispersion polymerization
Authors: Okubo M. , Miya T. , Minami H. , Takekoh R. 
Published: October 2004

AbstractNonspherical polystyrene (PS)/poly(n‐butyl methacrylate) (PBMA) composite particles with uneven surfaces were produced by seeded dispersion polymerization of BMA with 1.65‐μm, monodisperse, spherical PS seed particles. The composite particles consisted of a PS core and an incomplete PBMA shell. The formation mechanism of such nonspherical particles was discussed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2013–2021, 2002
Thermal properties of main‐chain phosphorus‐containing epoxide cured with amine
Authors: Cheng Kuo‐Chung , Yu Su‐Yun , Chiu Wen‐Yen 
Published: October 2004

AbstractA main‐chain phosphorus‐containing diepoxide, bis‐glycidyloxy phenylphosphate (BGPP), was synthesized, then blended with various contents of a 4,4′‐diglycidylether of bisphenol A (DGEBA)‐type epoxy resin, DER 331. The curing reactions of the blended resins with diethyltriamine (DETA) and the thermal properties of the cured specimens were investigated with an infrared spectrophotometer, a differential scanning calorimeter, and a thermogravimetry analyzer. The activation energy is 51.2 kJ/mol for the BGPP–DETA curing system, and it increases with the content of DER 331 for the BGPP–DER 331–DETA systems. The average apparent decomposition activation energies of the thermosets with phosphorus‐containing epoxide are from 147.3 to 165.1 kJ/mol, which are higher than that of the DER 331–DETA system (95.8 kJ/mol). The BGPP–DETA system shows a relatively higher char yield and limiting oxygen index (LOI) value, 29–31, but the thermoset with BGPP results in a decrease in the Tg. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2733–2740, 2002; DOI 10.1002/app.10160
Thermal properties of side‐chain phosphorus‐containing epoxide cured with amine
Authors: Cheng Kuo‐Chung , Yu Su‐Yun , Chiu Wen‐Yen 
Published: October 2004

AbstractGlycidyloxy diphenylphosphine oxide (GDPPO), a side‐chain phosphorus‐containing monoepoxide, was prepared. The compound, GDPPO, was mixed with 4,4′‐diglycidylether of bisphenol A‐type epoxy resin, DER 331. The reaction kinetics of the mixture, GDPPO–DER 331, cured with diethyltriamine (DETA), and the thermal decomposition properties of the thermosets were studied. For the GDPPO–DER 331–DETA curing systems, it was found that the activation energy of the curing reaction is 45.0 kJ/mol for the GDPPO–DETA system, and it decreases with the content of GDPPO. According to the method of Ozawa, the average apparent thermal decomposition activation energies of the thermosets with phosphorus‐containing monoepoxide are from 138.5 to 178.1 kJ/mol, which are higher than that of the DER 331–DETA system (95.8 kJ/mol). However, the lower crosslinking density and gel fraction of the system with the phosphorus‐containing monoepoxide, GDPPO, result in poor protection of the intumescent char during thermal decomposition; thus, the char yield and limiting oxygen index (LOI) of the cured specimens decrease with increasing GDPPO. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2741–2748, 2002; DOI 10.1002/app.10161
Structure–property relationships of poly(urethane urea)s with ultra‐low monol content poly(propylene glycol) soft segments. I. Influence of soft segment molecular weight and hard segment content
Authors: O'Sickey Matthew J. , Lawrey Bruce D. , Wilkes Garth L. 
Published: October 2004

AbstractStructure–property relationships in poly(urethane urea)s synthesized with ultra‐low monol content poly(propylene glycol) soft segments were investigated as soft segment molecular weight (2000, 4000, and 8000 g/mol) and hard segment content (6.3 and 9.0 wt %) were varied. Morphological features such as interdomain spacing and interphase thickness were quantified and revealed with small‐angle X‐ray scattering (SAXS) and atomic force microscopy (AFM). The thermal and mechanical behavior was assessed with a dynamic mechanical analyzer (DMA) and by differential scanning calorimetry (DSC) and stress‐strain tests. Hard segment content, over the limited range studied, had little effect on the morphology and soft segment thermal and mechanical properties. The molecular weight of the soft segments had considerably more influence on the morphology and mechanical properties. Increasing soft segment molecular weight resulted in greater interdomain spacings, as shown by SAXS, and a noticeable change in the structure, as shown by AFM. Additionally, as soft segment molecular weight decreased the soft segment glass transition broadened and rose to higher temperatures. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 229–243, 2002; DOI 10.1002/app.10168
Effects of the o‐aromatic ring in the molecular chain on the properties of polyester polyols
Authors: Zhu Qingzeng , Zhang Chen , Feng Shengyu , Chen Jianhua 
Published: October 2004

AbstractA series of liquid polyester polyols from adipic acid (AA), phthalic anhydride (PA), ethylene glycol, propanediol‐1,2, and trihydroxymethylpropane, varying in the molar ratio of PA to AA, were prepared. The effects of the o‐aromatic ring in the molecular chain, which came from PA, on the viscosity, glass‐transition temperature, and thermal degradation temperature of the polyester polyols were studied with viscometry, differential scanning calorimetry, and thermogravimetry. The intrinsic viscosity and glass‐transition temperature increased with the concentration of the o‐aromatic ring increasing. The temperature of the maximum thermal degradation rate for aliphatic polyester polyols was 434.20°C. Two steps of thermal degradation were found when there were o‐aromatic rings in the molecular chain. One thermal degradation temperature was 358.36–360.48°C, and the other was 412.85–427.18°C. Polyester polyols with o‐aromatic rings had higher stability at lower temperatures (<240.00°C). However, aliphatic polyester polyols had higher stability at higher temperatures (300.00–480.00°C). The activation energy and order of degradation were calculated from thermogravimetric curves. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1617–1624, 2002
Graft copolymerization of acrylic acid on methylcellulose by ceric ion/p‐xylene redox pair
Authors: Eromosele I. C. , Eromosele C. O. , Zanna H. K. 
Published: October 2004

AbstractThe graft copolymerization of acrylic acid onto methylcellulose by ceric ion/p‐xylene redox pair was investigated in aqueous media under homogeneous conditions. The graft yield dependency on p‐xylene concentration in the range 1.8–45.0 × 10−5M showed a minimum and an enhanced yield when the methylcellulose interacted with ceric ion and p‐xylene for an initial period of 10 min (preoxidation time) prior to addition of monomer to the reaction medium. This was attributed to the presence of two kinetically controlled reactions initiated by p‐xylyl radical and diradical species. At prolonged preoxidation times of 30 and 60 min, the graft yield dependency on p‐xylene concentration was normal and suggested the presence of only one initiating species. The effect of ceric ion on the graft reaction in the concentration range of 8.33–83.3 × 10−3M was optimal at 131% graft yield for ceric ion concentration of 16.7 × 10−3M and was reduced significantly by as much as 75% at the highest concentration of the latter. The temperature dependency of graft yield was negative in the region 30–50°C. At 50°C the initial rate of graft was only 37% of the value at 30°C. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 500–504, 2002; DOI 10.1002/app.10200
On‐line determination of the conversion in a styrene bulk polymerization batch reactor using near‐infrared spectroscopy
Authors: Lousberg H. H. A. , Boelens H. F. M. , Le Comte E. P. , Hoefsloot H. C. J. , Smilde A. K. 
Published: October 2004

AbstractA fast on‐line method for measuring the monomer conversion of a styrene batch polymerization reaction with near‐infrared spectroscopy (NIR) has been developed. Multivariate calibration was performed, using polymer samples having temperatures around the set point of the batch reactor (75–85°C) and monomer conversions up to 35%. The calibration model was built in such a way that the effect of the temperature on the predicted conversion of the sample was minimized. The method was validated in a number of batch runs. In these runs, the batch temperature and molar mass distributions of the polymer were varied. At‐line size‐exclusion chromatography was used as a reference method for measuring the monomer conversion. Results show that on‐line conversion monitoring with NIR offered overall an excellent accuracy (∼ 0.32% conversion). For high and low monomer conversions a small bias in the predicted conversion is present. The method proved to be insensitive to both relative large changes (10°C) of the batch temperature and to considerable changes of the molar mass distribution of the polymer. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 90–98, 2002; DOI 10.1002/app.10241
Characterization and properties of the neutral and doped blends of poly(3‐dodecylthiophene) with low‐density polyethylene
Authors: Qiao Xiuying , Wang Xianhong , Zhao Xiaojiang , Wang Yanju , Chen Qingyong , Mo Zhishen 
Published: October 2004

AbstractIn this paper, the structures and properties of the neutral and doped blends of poly(3‐dodecylthiophene) (P3DDT) with low‐density polyethylene (LDPE) were investigated. Wide‐angle X‐ray diffraction (WAXD), differential scanning calorimetry (DSC), Fourier transform infrared spectra (FTIR), and scanning electron microscopy (SEM) were used to characterize the structures and morphologies of the blends, and conductivity was also measured. It was found that separate crystallizations occur between P3DDT and LDPE. When the amount of P3DDT is small in the blend, it has the effect of a nucleation reagent and has some influence on the crystal structure. After doping, the interaction force between the molecular chains increases, and leads to a more compact packing and a more uniform dispersion in morphology. Through blending, the thermal stability of pure component could be greatly improved, especially when the P3DDT content is 5 wt %. The conductivity measurements indicate that the conductivity increases with the increase of the P3DDT composition and doping time. © 2002 John Wiley & Sons, Inc. J Appl Polym Sci 84: 741–749, 2002; DOI 10.1002/app.10247
Studies on compatibilization of intumescent flame‐retardant/PP composites based on etched PP
Authors: Ma Zhi‐Ling , Pang Xiu‐Yan , Zhang Jie , Ding Hai‐Tao 
Published: October 2004

AbstractThe phosphoric acid–pentaerythritol–melamine copolymer was selected as an intumescent flame retardant (IFR). The influence of dicromate acid–etching polypropylene (EPP) on the properties and compatibility of IFR/PP composites was studied. The results obtained from mechanical tests and SEM showed that EPP was a true coupling agent for IFR/PP blends, but without changing the necessary flame retardancy. The cocrystallization between bulk PP and PP segments of EPP was proved by WAXD analysis. Flow tests showed that the flow behavior of composites in the melt is that of a pseudoplastic liquid, which is almost insignificant for EPP affecting the rheological behavior of an IFR/PP composite. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 522–527, 2002; DOI 10.1002/app.10261