bluuebunny/crossref_metadata_2025 huggingface dataset:
Retention properties of efficient adsorbent to silver(I)
Authors: Rivas Bernabé L. , Pooley S. Amalia , Ruf Beatriz , Reyes Patricio , Cárdenas Galo
Published: October 2004

The binding capability of crosslinked poly(acrylic acid‐co‐2‐acrylamide‐2‐methyl‐1‐propane sulfonic acid) for silver(I) ions by the batch equilibrium method is investigated. The effects of the pH, temperature, time of contact, and resin–metal ion molar ratio on the retention ability are studied. The retention for silver(I) increases from 21.7% at pH 1 to 94.6% at pH 5. The adsorption capacity at pH 5 is 1.18 meq/g dry resin. The maximum load capacity at the optimum pH is determined. In order to recover the resin, elution runs in acid and basic media are carried out. The best eluent is 4M HNO3 (84.9%). Moreover, retention–elution cycles are performed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1501–1506, 2002
Dynamic mechanical properties of polycarbonate and acrylonitrile–butadiene–styrene copolymer blends
Authors: Más J. , Vidaurre A. , Meseguer J. M. , Romero F. , Pradas M. Monleón , Ribelles J. L. Gómez , Maspoch M. L. L. , Santana O. O. , Pagés P. , Pérez‐Folch J.
Published: October 2004

Blends of polycarbonate (PC) and poly(acrylonitrile‐co‐butadiene‐co‐styrene) (ABS) with different compositions are characterized by means of dynamic mechanical measurements. The samples show phase separation. The shift in the temperatures of the main dynamic mechanical relaxation shown by the blend with respect to those of the pure components is attributed to the migration of oligomers present in the ABS toward the PC in the melt blending process. A comparison with other techniques (dielectric and calorimetric analysis) and the application of the Takayanagi three block model confirm this hypothesis. In all the studied blend compositions (ABS weight up to 28.6%) the PC appears as the matrix where a disperse phase of ABS is present. The scanning and transmission electron microscopy micrographs show that the size of the ABS particles increases when the proportion of ABS in the blend increases. The FTIR results indicate that the interaction between both components are nonpolar in nature and can be enhanced by the preparation procedure. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1507–1516, 2002
Thermogravimetric study of degradation process of diglycidyl ether of bisphenol A–1,2‐diaminocyclohexane/calcium carbonate system
Authors: Núñez Lisardo , Castro A. , Villanueva M. , Núñez M. R. , Rial B.
Published: October 2004

The thermal degradation of the epoxy system consisting of diglycidyl ether of bisphenol A (BADGE, n = 0)–1,2‐diaminocyclohexane (DCH) containing calcium carbonate filler is studied by thermogravimetric analysis to determine the reaction mechanism of the degradation process. The value of the activation energy, which is necessary for this study, is calculated using various integral and differential methods. The values obtained using the different methods are compared to the value obtained by Kissinger's method (234.84 ± 15.12 kJ/mol), which does not require knowledge of the n‐order value of the reaction mechanism. All the experimental results are compared to master curves in the range of Doyle's approximation (5–35% of conversion). The analysis of the results suggests that the reaction mechanism is a sigmoidal A2 type. The thermodegradation mechanism is similar to that found for the same epoxy system without additives. However, for this last system the sigmoidal mechanism is an A4 type. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1528–1535, 2002
Effect of phenol derivatives on molecular dimensions of poly(N‐vinyl‐2‐pyrrolidone) in aqueous solution
Authors: Kirci Betül , Güner Ali
Published: October 2004

The unperturbed dimensions and thermodynamic parameters of poly(N‐vinyl‐2‐pyrrolidone) (PVP) were studied in aqueous solutions in the presence of certain phenolic cosolutes (phenol, catechol, hydroquinone, resorcinol, and phloroglucinol). The intrinsic viscosities at 25°C and the θ temperature, linear and thermodynamic expansions, and root mean square end to end distances were evaluated for the system that was employed. The sequence was obtained due to the effectiveness of the cosolutes in the order of phloroglucinol > resorcinol > hydroquinone > catechol > phenol. The effects of these cosolutes on the main thermodynamic parameters were reported to be due to the number and position of hydroxyl groups present. The thermodynamic interaction parameter was also evaluated and the enthalpic and entropic contributions were verified. The condition required for the θ temperature to correspond to a Flory interaction parameter of 0.5 was well provided, yielding a θ temperature of almost 0.5 for the system under study. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 473–477, 2002; DOI 10.1002/app.10047
Synthesis and characterization of novel aromatic ether nitrile monomer containing propenylphenoxy groups and properties of its copolymer with 4,4′‐bismaleimidodiphenylmethane
Authors: Fang Qiang , Ding Xuemei , Wu Xiongying , Yue Yi , Jiang Luxia
Published: October 2004

A novel aromatic ether nitrile monomer containing propenyl groups, 2,6‐di{2‐[(E)‐1‐propenyl]phenoxy} benzonitrile (DPPB), was synthesized by the reaction of 2,6‐dichlorobenzonitrile and 2‐allylphenol using anhydrous potassium carbonate as the acid acceptor, N‐methyl pyrrolidone as the dipolar aprotic solvent, and toluene as the dehydrating agent. The chemical structure of DPPB was characterized by FTIR and 1H‐NMR. The monomer was used to modify a popular commercial bismaleimide, 4,4‐bismaleimidodiphenylmethane (BMDPM), to improve the shear strength of the resin. The results showed that DPPB could effectively improve the shear strength of the BMDPM resin without decreasing the heat resistance of BMDPM. A better result was obtained when the composition of DPPB in the copolymer was 45 wt %. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1465–1472, 2002
Toughening and reinforcing in rigid inorganic particulate filled poly(propylene): A review
Authors: Liang Ji‐Zhao
Published: October 2004

The recent advances in the toughening and reinforcing methods and theories in rigid inorganic particulate (RIP)‐filled poly(propylene) (PP) composites have been reviewed. Studies have shown that under given conditions, in addition to the obvious increase of modulus, an obvious brittle–ductile transition also appears in these composites. The key to toughening a polymer is the role that inclusions can play as agents that (1) induce extensive plastic deformation following the interfacial debonding between the inclusion itself and the matrix, (2) induce shear yielding of the matrix, and (3) terminate the propagation of cracks. The main factors with regard to reinforcing mechanisms are how to enhance the interfacial bonding between the particles and the matrix and how to improve the dispersion of inclusions in the matrix. The major theories interpreting the toughening mechanisms of polymer–RIP composites include micro‐voiding theory, damage competition theory, shear yielding theory, etc. It is necessary to form a soft shell/hard core structure to simultaneously toughen and reinforce polymers. Therefore, RIPs should be encapsulated with an elastic thin layer. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1547–1555, 2002
Synthesis and characterization of the epoxyfumarate resins
Authors: Matynia T. , Księżopolski J. , Gawdzik B.
Published: October 2004

The synthesis and properties of the new epoxyfumarate and epoxymaleate resins obtained by the addition of acidic allyl maleate to the commercially available resin Epidian 5 are presented. The resins were synthesized in one‐ and two‐step procedures and properties of the obtained resins are compared. It should be noted that the use of allyl alcohol in the synthesis of unsaturated resins has an advantageous influence on their properties. Glass‐transition temperatures of the epoxyfumarate resins exceed 100°C, whereas those of epoxymaleates are higher than 70°C. The resins are also characterized by good chemical resistance. © 2002 John Wiley & Sons, Inc. J Appl Polym Sci 84: 716–722, 2002; DOI 10.1002/app.10067
Electroinduced dispersion polymerization of acrylonitrile in the presence of poly(acrylic acid) and catalytic amount of CE(IV)
Authors: Saraç A. S. , Ustamehmetoglu B. , Yildirim H.
Published: October 2004

Electroinduced dispersion polymerization of acrylonitrile initiated by Ce(IV) was performed in an electrolytic cell in the presence of poly(acrylic acid) (PAA). Micron‐size polyacrylonitrile (PAN) particles were stabilized with PAA by electrostatic interaction or by a PAA–Ce(III)–PAN ternary complex formation. A PAA–PAN stable polymer was formed in the cathodic compartment, and the reduced initiator was reoxidized in the anode, thus allowing for the continuation of the process. A possible mechanism of polymerization is suggested. © 2002 John Wiley & Sons, Inc. J Appl Polym Sci 84: 723–728, 2002; DOI 10.1002/app.10076
Plasma‐induced copolymerization of hydrochloride of N,N‐dimethylaminoethyl methacrylate and acrylamide
Authors: Lu Jianmei , Cheng Zhenping , Zhu Xiulin , Zhang Lifen
Published: October 2004

A super alcohol‐absorbing resin, with absorbency of 106 g/g for methanol, was polymerized from the hydrochloride of N,N‐dimethylaminoethyl methacrylate (DM) and acrylamide (AM) by plasma‐induced polymerization at lower temperatures in water solutions. Many factors affecting the absorbing properties, such as post‐polymerization time, monomer concentration, plasma duration, plasma discharge power, monomer ratio, et al., were studied. The reasons for the absorbing alcohol of resins was also discussed. © 2002 John Wiley & Sons, Inc. J Appl Polym Sci 84: 729–734, 2002; DOI 10.1002/app.10086
Ionic conductivity and interfacial properties of polymer electrolytes based on PEO and boroxine ring polymer
Authors: Yang Yunsong , Inoue T. , Fujinami T. , Mehta M. A.
Published: October 2004

Blended polymer electrolytes based on poly(ethylene oxide) (PEO) and boroxine ring polymer (BP) solvated with lithium triflate were formulated and evaluated. Compared to PEO–salt polymer electrolyte, ionic conductivities of blended polymer electrolytes were two orders of magnitude higher in a low‐temperature range; as well, lithium transference numbers were increased to ∼ 0.4. These were due to the increased mobility and anion trapping of boroxine rings. BP also exhibited the stabilizing effect on lithium–polymer electrolyte interface, and a reduced interfacial resistance between lithium metal and the polymer electrolyte was found with increasing of BP content. Polymer electrolytes based on PEO and BP are suitable for use in lithium secondary battery. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 17–21, 2002; DOI 10.1002/app.10090
A comprehensive model for solid‐state polycondensation of poly(ethylene terephthalate): Combining kinetics with crystallization and diffusion of acetaldehyde
Authors: Wang Xia‐Qin , Deng De‐Chun
Published: October 2004

A comprehensive mathematical model was established by considering the main and side reactions for solid‐state polycondensation of poly(ethylene terephthalate). The effect of temperature on chain mobility was used to estimate the rate constants of chemical reactions. The polymer crystalline fraction was modeled as containing only repeat units, thus concentrating end groups and condensates in the amorphous fraction. The diffusion coefficient of acetaldehyde was calculated by the model. The simulation results of this comprehensive model were validated by experimental data reported in literature. The model predictions were important clues for further experimental study on poly(ethylene terephthalate) solid‐state polycondensation. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 3133–3144, 2002; DOI 10.1002/app.10113
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

An 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

Amorphous, 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

Blends 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

Interpenetrating 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

The 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

Attenuated 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

In 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

The 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

Supertough 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

Nonspherical 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

A 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

Glycidyloxy 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

Structure–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

A 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

The 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

A 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

In 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

The 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
Effect of grafting with acrylic monomers on the viscosity, gelatinization temperature, and granule swelling characteristics of starch
Authors: Aravindakshan P. , Kumar V. G.
Published: October 2004

Amylography and scanning electron microscopy (SEM) studies on grafted copolymers of starch with methacrylic acid and methyl methacrylate demonstrated significant changes in the viscosity and granule disintegration characteristics, depending on the extent of grafting and the nature of the monomer. Marked viscosity changes were observed when the carboxyl groups of the starch‐graft‐poly(methacrylic acid) (SPMAA) were neutralized with sodium hydroxide. The viscosity modification was found to be dependent on the extent of neutralization, and a maximum was observed at 10–25% neutralization. With an increase in extent of neutralization, there was a decrease in gelatinization temperature. For a sample of SPMAA with a percentage grafting of 14.1, the gelatinization temperature decreased from 64°C for the acid form to 42°C for the fully neutralized form. The gelatinization temperature of the fully neutralized samples of SPMAA showed a linear relationship with the percentage grafting. SEM was used to elucidate the effect of grafting on the granule swelling characteristics of starch at various temperatures. In the case of starch‐graft‐polymethyl methacrylate (SPMMA), granule disruption on heating with water was observed. However, this did not lead to the build‐up of viscosity on gelatinization. This was explained to be caused by the hydrophobic nature of SPMMA. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 528–534, 2002; DOI 10.1002/app.10266
Semicrystalline polyimide matrices for composites: Crystallization and properties
Authors: Yudin V. E. , Svetlichnyi V. M. , Gubanova G. N. , Didenko A L. , Sukhanova T. E. , Kudryavtsev V. V. , Ratner S. , Marom G.
Published: October 2004

New semicrystalline polyimide/oligoimide blends, designated for matrices in carbon fiber‐reinforced composites, were developed. A specific advantage of the proposed polyimides is their ability to crystallize from the melt, therein retaining their crystallinity throughout the manufacturing process. The generation of crystallinity after melting, referred to as recrystallization, was investigated here as affected by blending the polyimides with oligoimides of a similar chemical structure. Based on thermal analysis and enthalpy measurements, comparative X‐ray diffraction analyses, and polarized light microscopy of hot‐stage‐controlled crystallization, the recrystallization ability was determined for five different oligoimides. In some cases, the addition of oligoimides, both amorphous and crystalline, resulted in complete recrystallization. The main contribution of the oligoimides is suggested to be through plasticization, allowing segmental chain mobility during crystallization, and not via nucleation. A similar effect was obtained by lowering the molecular weight of the polyimide; this, however, generates mechanical property reduction, rendering the polyimide irrelevant to composite materials. Finally, it was shown that crystallization was also enhanced by carbon fibers, serving as a nucleating agent and generating transcrystallization. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2873–2882, 2002; DOI 10.1002/app.10277
Modification of polyolefins with silicone copolymers. II. Thermal, mechanical, and tribological behavior of PP and HDPE blended with silicone copolymers
Authors: Yilgor Emel , Sinmazcelik Tamer , Yilgor Iskender
Published: October 2004

Thermoplastic polyolefin (TPO) films with permanent, silicone‐rich, low‐friction, low‐abrasion surfaces were obtained by melt blending of high‐density polyethylene (HDPE) and polypropylene (PP) with polydimethylsiloxane (PDMS)‐containing block copolymers. Two different block copolymers, a siloxane–urea segmented copolymer and a polycaprolactone‐b‐PDMS triblock copolymer were used as modifiers at levels between 0.1 and 5.0% by weight. Blends were prepared in a twin‐screw extruder. Modified films displayed surfaces with very low friction coefficients and high abrasion resistance, which depended on the type and the level of additive incorporated into the system. Bulk properties of these modified systems, such as crystallization and melting behavior or tensile properties, were not affected. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 535–540, 2002; DOI 10.1002/app.10279
Surface morphology evaluation of polymer beads based on divinylbenzene by atomic force microscopy
Authors: Neves Márcia A. F. S. , Coutinho Fernanda M. B. , Dias Marcos L. , Simão Renata A. , Achete Carlos A.
Published: October 2004

Macroporous poly(styrene‐co‐divinylbenzene) and poly(divinylbenzene) beads were synthesized by modified suspension polymerization in the presence of different mixtures of toluene and heptane as porogen agent. Through atomic force microscopy, it was possible to identify the microspheres and the channels between them that constitute the bead pores. It was also possible to make a comparison with the results obtained by nitrogen desorption, a traditional technique used to determine the porosity of macroporous copolymers in the dry state. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 541–551, 2002; DOI 10.1002/app.10290
Syntheses of bismaleimides with ester units and their polymerization with diamines
Authors: Sava M.
Published: October 2004

Five structurally different bismaleimides were synthesized by reaction between 3(4)‐maleimidobenzylchloride with various diphenols. They were characterized by infrared (IR) and proton nuclear magnetic resonance (1H‐NMR) spectroscopy. Thermal characterization of monomers and their polymers was accomplished by differential scanning calorimetry (DSC) and dynamic thermogravimetric analysis (TGA). Polyaminobismaleimides having inherent viscosities of 0.1–0.4 dL/g were prepared by Michael addition of diamines to bismaleimides. The polymers are soluble in solvents as DMF, NMP, and DMSO, and afforded film from their solutions. © 2002 John Wiley & Sons, Inc. J Appl Polym Sci 84: 750–757, 2002; DOI 10.1002/app.10294
Liquid crystalline copolyester/polyethylene in situ composite film: Rheology, morphology, molecular orientation, and tensile properties
Authors: Nakinpong Teeranant , Bualek‐Limcharoen Sauvarop , Bhutton Angkana , Aungsupravate Ornsiri , Amornsakchai Taweechai
Published: October 2004

A thermotropic liquid crystalline copolyester (TLCP) was blended with low density polyethylene using a corotating twin screw extruder and then fabricated by extrusion through a miniextruder as cast film. Rheological behavior, morphology, and tensile properties of the blends were investigated. Melt viscosities of neat components and blends measured by using plate‐and‐plate and capillary rheometers at 240°C, in the shear rate range 1–104 s−1, showed similar shear thinning effect. The viscosity values measured by the two techniques in the overlapping range of shear rate are found to be identical, which is in accord with the Cox–Merz rule. Addition of TLCP slightly reduces the matrix melt viscosity. TLCP dispersed phase in the extruded strand appeared in the form of spherical droplets. These droplets were elongated into fibrils with high aspect ratio (length to width) at the film extrusion step. As a result, the Young's modulus in machine direction (MD) of the composite film was greatly enhanced. At 20 wt % of TLCP, the MD Young's modulus was found to be about 16‐fold increase compared to that of the neat polyethylene film. However, the elongation at break sharply dropped with the increase of TLCP content. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 561–567, 2002; DOI 10.1002/app.10307
Effect of compatibilization in injection‐molded polycarbonate and liquid crystalline polymer blend
Authors: Tan L. P. , Yue C. Y. , Tam K. C. , Lam Y. C. , Hu X.
Published: October 2004

The effect of compatibilizing polycarbonate (PC) and LC5000, a thermotropic liquid crystalline polymer consisting of 80/20% of hydroxybenzoic acid and poly(terephthalate) with a laboratory synthesized compatibilizer was studied. The compatibilizer was synthesized by transesterification of PC and LC5000 with the aid of a catalyst. The effect of compatibilization was investigated by studying the mechanical and morphological properties of injection‐molded plaques with different thicknesses. Substantial improvement was observed in the mechanical properties after compatibilization. Significant enhancement in the fibrillation was also observed in the samples after addition of compatibilizer. The surface finish of the compatibilized samples was smooth and homogenous as compared to the uncompatibilized samples. The skin‐core phenomenon in the tensile fractured surfaces was less obvious in the former samples, indicating better adhesion and homogeneity. These morphological studies showed that the mechanical properties enhancement lay in improved fibrillation and interfacial adhesion between the dispersed and major phases. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 568–575, 2002; DOI 10.1002/app.10308
Novel high‐solids pigmented coatings prepared from a new‐synthesized isophthalate‐based oligoester, a melamine resin, and various fillers
Authors: Diakoumakos Constantinos D. , Jones Frank N.
Published: October 2004

A new‐synthesized hydroxyl‐terminated isophthalate‐based liquid oligoester (L‐311), an hexakis(methoxymethylol)melamine resin, and various inert pigments (fillers) such as either kaolins (Al2O3 · 2SiO2 · 2H2O) of different particle sizes (1.50 and 4.80 μm) or calcium metalsilicate (CaSiO3) were used to prepare high‐solids pigmented coatings (PA and PW series, respectively). The physical, chemical, and mechanical properties (pencil hardness, Knoop hardness, flexibility, impact resistance, adhesion, gloss, solvent, and mar resistance) of the new‐formulated pigmented coatings were correlated to the chemical species of the filler, the filler's load and particle size, the quantity of the crosslinker, and the introduction of large particle size colloidal silica into the coating. For measuring the mar resistance of the pigmented coatings, the Taber abrasion method was applied and the inverse wear index, F [=I−1, cycles/cg (wear index l, weight loss (cg) per number of cycles)], was directly related to the mar resistance. Either when kaolins or calcium metalsilicates were used as fillers, the Knoop hardness, the impact, and mar resistance of the films were affected from the filler's load, whereas the quantity of melamine resin (crosslinker) affected the knoop hardness, the gloss, and the mar resistance. The fillers' particle size and the introduction of large particle colloidal silica affected mainly the mar resistance and the gloss, respectively. The pencil hardness of the PW‐pigmented coatings series (F‐2H) was higher than that of the PA‐series (B‐HB). The chemical composition of the inert pigment proved to be a very important parameter in the preparation of pigmented coatings with specific properties that aim to meet modern and particular demands for various end‐up uses. All the new‐formulated high‐solids (nonvolatiles by weight ∼ 70%) pigmented coatings (PA and PW series) presented excellent adhesion (5B), flexibility (> 32%), methyl ethyl ketone (MEK) resistance (>200 rubs), high pencil hardness, good knoop hardness, and very good impact resistance (from 100 up to 160 in.‐lb), independently of the species of the filler (kaolins or calcium metalsilicate). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 576–590, 2002; DOI 10.1002/app.10309
Rigid polyurethane foam prepared from a rape seed oil based polyol
Authors: Hu Yan Hong , Gao Yun , Wang De Ning , Hu Chun Pu , Zu Stella , Vanoverloop Lieve , Randall David
Published: October 2004

A new kind of polyol based on rape seed oil for use in rigid polyurethane foam was synthesized and characterized. The synthesis of such a polyol was divided into two steps. The first step was the hydroxylation of the double bonds existing in the long chains of the unsaturated aliphatic hydrocarbon of rape seed oil with peroxy acid. The second step was use of the alcoholysis of the hydroxylated rape seed oil with triethanolamine to increase the hydroxyl value of the product. The reaction process was monitored by means of a novel on‐line infrared spectrometer. Rigid polyurethane foam was produced with this rape seed oil based polyol and some physical properties of the foam were examined and compared with a reference foam. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 591–597, 2002; DOI 10.1002/app.10311