bluuebunny/crossref_metadata_2025_split huggingface dataset:
The predictive validity of the Phelps Kindergarten Readiness Scale
Authors: Augustyniak Kristine M. , Cook‐Cottone Catherine P. , Calabrese Nancy 
Published: March 2004

AbstractThis study assesses the predictive validity of the Phelps Kindergarten Readiness Scale (PKRS) for later academic achievement and explores the utility of a domain‐specific measure of kindergarten readiness. Kindergarten readiness scores were significantly correlated with both math and language arts achievement as measured by New York State fourth‐grade assessments for 148 students in a suburban, northeastern public school. In addition, each of the PKRS domains (Verbal, Perceptual, and Auditory) was correlated with later academic achievement. Two simultaneously calculated regression analyses showed that language arts skills were best predicted by the Verbal and Auditory domains of the PKRS and that math achievement was more complexly determined by all three readiness domains. Structural equation modeling using AMOS‐4 showed that the latent construct readiness, as measured by the PKRS domain scores, was positively and significantly related to the latent construct academic achievement. Finally, this relationship held when age, gender, and behavioral indices at the time of kindergarten screening were used as moderator variables. © 2004 Wiley Periodicals, Inc. Psychol Schs 41: 509–516, 2004.
Using MMPI‐A profiles to predict success in a military‐style residential treatment program for adolescents with academic and conduct problems
Authors: Weis Robert , Crockett Thomas E. , Vieth Sasha 
Published: March 2004

AbstractMilitary‐style residential treatment for adolescents with academic and conduct problems is an increasingly popular alternative to traditional school‐based services. However, dropout from “boot camp” programs is a primary reason for their high cost. Social‐emotional functioning before referral may differentiate adolescents who successfully complete these programs from those who withdraw. Minnesota Multiphasic Personality Inventory‐Adolescent (MMPI‐A; Butcher et al., 1992) responses of 225 adolescents (16–18 years) with histories of truancy and antisocial behavior were subjected to profile analysis prior to participation in a 22‐week, military‐style treatment program. Elevations on the F (Frequency), 1 (Hs), and 3 (Hy) scales differentiated adolescents who dropped out of these programs from those who graduated. Logistic regression showed prediction accuracy to be 75%. School psychologists may use MMPI‐A profiles, especially the 1/3 code type, to screen boot camp candidates, maximize adolescents' likelihood of success, and reduce costs due to attrition. © 2004 Wiley Periodicals, Inc. Psychol Schs 41: 563–574, 2004.
Polymerization of methyl acrylate with triphenylbismuthonium 1,2,3,4‐tetraphenylcyclopentadienylide as a new radical initiator
Authors: Tripathi Seema , Srivastava A. K. 
Published: March 2004

AbstractTriphenylbismuthonium 1,2,3,4‐tetraphenylcyclopentadienylide in 1,4‐dioxan initiated radical polymerization of methyl acrylate to ∼30% conversion without gelation because of autoacceleration. The polymer had a viscosity‐average molecular weight of 200,000. The kinetic expression was Rpα[I]0.3[M]1.16, that is, the system followed nonideal kinetics because of primary radical termination and degradative chain‐transfer reactions. The values of kkt and the energy of activation were computed as 3.12 × 10−5 Lmol−1s−1 and 28 kJ/mol, respectively. The ylide dissociated to form a phenyl radical, which brought about polymerization of methyl acrylate. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2060–2065, 2004
Copolymerization of the macromonomer poly(ethylene oxide) with styryl end group and styrene in the presence of poly(ε‐caprolactone) with 2,2,6,6‐tetramethylpiperidinyl‐1‐oxy end group by controlled radical mechanism
Authors: Wang Yun , Lu Guangqiang , Huang Junlian 
Published: March 2004

AbstractA copolymerization of macromonomer poly(ethylene oxide) (PEO) with a styryl end group (PEOS) and styrene was successfully carried out in the presence of poly(ε‐caprolactone) (PCL) with 2,2,6,6‐tetramethylpiperidinyl‐1‐oxy end group (PCLT). The resulting copolymer showed a narrower molecular weight distribution and controlled molecular weight. The effect of the molecular weight and concentration of PCLT and PEOS on the copolymerization are discussed. The purity of PEOS exerted a significant effect on the copolymerization; when the diol contents of PEO macromonomer were greater than 1%, the crosslinking product was found. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2093–2099, 2004
13C NMR determination of the microstructure of polypropylene obtained with the DADNi(NCS)2/methylaluminoxane catalyst system
Authors: Barrera Galland Griselda , Da Silva Luciana P. , Dias Marcos L. , Crossetti Geraldo L. , Ziglio Cláudio M. , Filgueiras Carlos A. L. 
Published: March 2004

AbstractA complete 13C NMR characterization of a polymer synthesized with a new Ni‐diimine complex [DADNi(NCS)2, where DAD = 2,6‐iPrC6H3NC(Me)C(Me) N2,6‐iPrC6H3] activated by methylaluminoxane by homopolymerization of propylene is presented. The amorphous material was made up mainly of blocks of syndiotactic polypropylene and ethylene–propylene copolymer. Some degree of propylene inversion (<1.2 mol %) and of long isobutyl and 2‐methyl hexyl branching (<1 mol %) were assigned and quantified. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2171–2178, 2004
Preparation of cationic latices comprising hollow thermostable particles
Authors: Pavlyuchenko V. N. , Sorochinskaya O. V. , Primachenko O. N. , Byrdina N. A. , Ivanchev S. S. , Skrifvars M. 
Published: March 2004

AbstractA method is described for the preparation of cationic latices comprising submicron hollow particles for a possible application as a thermally stable polymeric pigment in coatings or pigmented compositions on the basis of thermosetting polymers cured at temperatures up to 170–190 °C. The method is based on the deposition of melamine–formaldehyde resin in the form of cationic colloid onto anionic hollow particles resulting in the recharging of anionic hollow particles and the formation of an outer melamine shell, which provides thermal stability of the hollow particles at curing and application of pigmented coatings and compositions. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2225–2234, 2004
New poly(p‐phenylene vinylene) derivatives with two oxadiazole rings per repeat unit: Synthesis, photophysical properties, electroluminescence, and metal ion recognition
Authors: Mikroyannidis John A. , Spiliopoulos Ioakim K. , Kasimis Theodoros S. , Kulkarni Abhishek P. , Jenekhe Samson A. 
Published: March 2004

AbstractTwo new poly(p‐phenylene vinylene) derivatives OX1‐PPV and OX2‐PPV bearing two 1,3,4‐oxadiazole rings per repeat unit and a fully conjugated backbone with solubilizing dodecyloxy side groups were synthesized and investigated. The amorphous conjugated polymers had glass‐transition temperature values of 60–75 °C and emitted intense blue or greenish‐blue light in solution with photoluminescence (PL) emission maxima at 379–492 nm and PL quantum yields of 0.41–0.52. In the solid state they emitted yellowish‐green light with PL emission maxima at 533–555 nm. Cyclic voltammetry showed that both conjugated polymers had reversible reduction and irreversible oxidation, making them n‐type materials. The electron affinity of OX2‐PPV was estimated as 2.85 eV whereas that of OX1‐PPV was 2.75 eV. Yellow electroluminescence (EL) was achieved from single‐layer light‐emitting diodes of OX2‐PPV with an EL emission maximum at 555 nm and a brightness of 70 cd/m2. Polymer OX2‐PPV, which was functionalized with 2,6‐bis(1,3,4‐oxadiazole‐2‐yl)pyridine, demonstrated sensitivity to various metal ions as a fluorescence‐mode chemosensor. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2112–2123, 2004
Synthesis of a soluble pyrrole copolymer with phenetidine
Authors: Li Xin‐Gui , Chen Run‐Feng , Huang Mei‐Rong , Zhu Mei‐Fang , Chen Qun 
Published: March 2004

AbstractA new series of copolymers was synthesized through the oxidative polymerization of pyrrole (PY) and o‐phenetidine (PHT) with inorganic oxidants in acidic media. The polymerization parameters including the mixing method of the oxidant with the comonomer, the comonomer ratio, the time, the temperature, the oxidant, the organic medium, and the acid were systematically optimized for the synthesis of copolymers with high yields, intrinsic viscosities, and solubility. The resultant copolymers were characterized by elemental analysis, infrared, ultraviolet–visible, solution high‐resolution 1H NMR and solid‐state high‐resolution 13C NMR, circular dichroism spectroscopy, and cyclic voltammetry. The results showed that the PY observed content in the copolymers was much higher than the PY feed content. The regular variation of the polymerization yield, intrinsic viscosity, solubility, macromolecular structure, and electroactivity of the resulting polymers with the comonomer ratio, together with the complete solubility of a PY/PHT (10/90) polymer in highly polar solvents, indicated the formation of real random copolymers containing both PY and PHT units rather than a mixture of two homopolymers. However, the polymers containing more than 59 mol % PY were not homogeneous copolymers consisting of soluble and insoluble parts. A semiquantitative relationship between the polymerization yield or solubility of the copolymers and the polarity index of the organic solvents was examined. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2073–2092, 2004
Novel amphiphilic network polymers consisting of nonpolar, short primary polymer chains and polar, long crosslink units: Influence of characteristic dangling chains on swelling behavior of resulting amphiphilic gels
Authors: Doura Masato , Aota Hiroyuki , Matsumoto Akira 
Published: March 2004

AbstractNovel amphiphilic network polymers consisting of nonpolar, short primary polymer chains and polar, long crosslink units were prepared, and the swelling behavior of resulting amphiphilic gels is discussed by focusing on the influence of characteristic dangling chains; that is, benzyl methacrylate (BzMA) was copolymerized with tricosaethylene glycol dimethacrylate [CH2C(CH3)CO(OCH2CH2)23OCOC(CH3)CH2, PEGDMA‐23] in the presence of lauryl mercaptan as a chain‐transfer agent because BzMA forms nonpolar, short primary polymer chains and PEGDMA‐23 as a crosslinker contains a polar, long poly(oxyethylene) unit. The enhanced incorporation of dangling chains into the network polymer was brought by shortening the primary polymer chain length, and copolymerization with methoxytricosaethylene glycol methacrylate, a mono‐ene counterpart of PEGDMA‐23, enforced the incorporation of flexible dangling poly(oxyethylene) chains into the network polymer, although the former dangling chains as terminal parts of primary poly(BzMA) chains were rather rigid. Then, the influence of characteristic dangling chains on the swelling behavior of amphiphilic gels was examined in mixed solvents consisting of nonpolar t‐butylbenzene and polar methanol. The profiles of the solvent‐component dependencies of the swelling ratios were characteristic of amphiphilic gels. The introduction of dangling poly(oxyethylene) chains led not only to an increased swelling ratio but also to sharpened swelling behavior of amphiphilic gels. The swelling response of amphiphilic gels was checked by changing the external solvent polarity. The dangling chains with freely mobile end segments influenced the swelling response of gels. The amphiphilic gels with less entangled, collapsed crosslink units exhibited faster swelling response than the ones with more entangled, collapsed primary polymer chains. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2192–2201, 2004
Hydrogels based on physiologically clotted fibrin–gelatin composites
Authors: Noorjahan S. E. , Sastry T. P. 
Published: March 2004

AbstractFibrin–gelatin composite (PFG) films were prepared and crosslinked with glutaraldehyde as reported by us previously. These composites were graft‐copolymerized with poly(2‐hydroxyethyl methacrylate) (PHEMA) and poly(2‐hydroxypropyl methacrylate) (PHPMA) with a potassium persulfate and sodium metabisulfite redox initiation system. The graft copolymers (PFG‐HEMA and PFG‐HPMA) were characterized for their percentage of grafting, percentage of equilibrium water content, and percentages of free water and bound water. The chemical composition and thermal, mechanical, morphological, and surface characteristics were also evaluated. The optimum conditions for obtaining a maximum percentage of grafting were standardized. PFG and its graft copolymers exhibited higher equilibrium water contents ranging from 60 to 77% when compared with those of HEMA and HPMA homopolymers. DSC studies revealed increased freezing water contents and decreased bound‐water contents for the graft copolymers when compared with those of PFG alone. These properties improved the efficacy of hydrogels. PFG demonstrated better mechanical properties as compared with its graft copolymers. This may be attributed to the alkaline reaction conditions wherein protein hydrolysis of PFG would have occurred thereby reducing the overall strength of the graft copolymers. IR and scanning electron microscopic studies confirmed the grafting of PHEMA and PHPMA onto PFG. Contact‐angle studies revealed increased polarity for graft copolymers, which is a symbol for increased hydrophilicity. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2241–2252, 2004
Solid polymer electrolytes I, preparation, characterization, and ionic conductivity of gelled polymer electrolytes based on novel crosslinked siloxane/poly(ethylene glycol) polymers
Authors: Kuo Ping‐Lin , Hou Sheng‐Shu , Lin Chung‐Yie , Chen Chi‐Chang , Wen Ten‐Chin 
Published: March 2004

AbstractA series of crosslinked siloxane/poly(ethylene glycol) (Si–PEG) copolymers were synthesized from the reactive methoxy‐functional silicone resin (Si resin) and PEGs with different molecular weights via two kinds of crosslinking reactions during an in situ curing stage. One of the crosslinking reactions is the self‐condensation between two methoxy groups in the Si resin, and another one is an alkoxy‐exchange reaction between the methoxy group in the Si resin and the OH group in PEG. The synthesized crosslinked copolymers were characterized by Fourier transform infrared spectroscopy, DSC, and 13C NMR. The crosslinked copolymers were stable in a moisture‐free environment, but the SiOC linkages were hydrolyzed in humid conditions. The gel‐like solid polymer electrolytes (SPEs) were prepared by impregnating these crosslinked Si–PEG copolymers in a propylene carbonate (LiClO4/PC) solution. The highest conductivity reached 2.4 × 10−4 S cm−1 at 25 °C and increased to 8.7 × 10−4 S cm−1 at 85 °C. The conductivities of these gel‐type SPEs were affected by the content of LiClO4/PC, the molecular weights of PEGs, and the weight fraction of the Si resin. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2051–2059, 2004
Efficient and rapid synthesis of polyureas and polythioureas from the reaction of urea and thiourea with diamines under microwave irradiation
Authors: Banihashemi Ahmad , Hazarkhani Hassan , Abdolmaleki Amir 
Published: March 2004

AbstractPolyureas and polythioureas were readily synthesized by the reaction of aromatic and aliphatic amines with urea and thioureas, respectively, in good to excellent yields under microwave irradiation. The effects of the microwave irradiation time and power, the nature of the solvent, and the solid content of the monomers on the inherent viscosity of the polymers were investigated. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2106–2111, 2004
Nanoencapsulation of a hydrophobic compound by a miniemulsion polymerization process
Authors: Luo Yingwu , Zhou Xiangdong 
Published: March 2004

AbstractThe nanoencapsulation of hydrophobic compounds by miniemulsion polymerization, a convenient one‐step encapsulation technique for nanocapsules, was investigated in terms of the thermodynamics and kinetics. The encapsulation was achieved by polymerization inducing phase separation within minidroplets dispersed in an aqueous phase. Thermodynamic factors (the level and type of surfactant, the level of the hydrophilic comonomer, and the monomer/paraffin ratio), kinetic factors (the level of the crosslinking agent or chain‐transfer agent), and nucleation modes were all found to have a great influence on the latex morphology. Specifically, for a styrene/paraffin system, there were optimum levels of sodium dodecyl sulfate (1.0 wt %), the hydrophilic comonomer (1.0 wt % methyl acrylate acid), and the chain‐transfer agent (0.2 wt % n‐dodecanethiol) for obtaining well‐defined nanocapsules of paraffin with a styrene/paraffin ratio of 1:1. When the styrene/paraffin ratio was reduced, however, it was more difficult to achieve a fully encapsulated particle morphology. Homogeneous nucleation could compete with encapsulation, and this resulted in a pure polymer particle and a half‐moon morphology. Conditions were also found under which complete encapsulation could be observed with a water‐soluble initiator (potassium persulfate), contrary to certain reports. Replacing potassium persulfate with an oil‐soluble initiator (2,2‐azobisisobutyronitrile) had little influence on the morphology under those conditions. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2145–2154, 2004
Crosslinkable poly(p‐phenylenevinylene) derivative
Authors: Sun Honghao , Liu Ze , Hu Yufeng , Wang Lixiang , Ma Dongge , Jing Xiabing , Wang Fosong 
Published: March 2004

AbstractTo simplify the fabrication of multilayer light‐emitting diodes, we prepared a p‐phenylenevinylene‐based polymer capped with crosslinkable styrene through a Wittig reaction. Insoluble poly(p‐phenylenevinylene) derivative (PPVD) films were prepared by a thermal treatment. The photoluminescence and ultraviolet–visible (UV–vis) absorbance of crosslinked films and noncrosslinked films were studied. We also studied the solvent resistance of crosslinked PPV films with UV–vis absorption spectra and atomic force microscopy. Double‐layer devices using crosslinked PPVD as an emitting layer, 2‐(4‐tert‐butylphenyl)‐5‐phenyl‐1,3,4‐oxadiazole (PBD) in poly(methyl methacrylate) as an electron‐transporting layer, and calcium as a cathode were fabricated. A maximum luminance efficiency of 0.70 cd/A and a maximum brightness of 740 cd/m2 at 16 V were demonstrated. A 12‐fold improvement in the luminance efficiency with respect to that of single‐layer devices was realized. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2124–2129, 2004
Synthesis and properties of novel polyimides derived from 2,2′,3,3′‐benzophenonetetracarboxylic dianhydride
Authors: Fang Xing‐Zhong , Li Qing‐Xuan , Wang Zhen , Yang Zheng‐Hua , Gao Lian‐Xun , Ding Meng‐Xian 
Published: March 2004

AbstractA new synthetic route to 2,2′,3,3′‐BTDA (where BTDA is benzophenonetetracarboxylic dianhydride), an isomer of 2,3′,3′,4′‐BTDA and 3,3′,4,4′‐BTDA, is described. Single‐crystal X‐ray diffraction analysis of 2,2′,3,3′‐BTDA has shown that this dianhydride has a bent and noncoplanar structure. The polymerizations of 2,2′,3,3′‐BTDA with 4,4′‐oxydianiline (ODA) and 4,4′‐bis(4‐aminophenoxy)benzene (TPEQ) have been investigated with a conventional two‐step process. A trend of cyclic oligomers forming in the reaction of 2,2′,3,3′‐BTDA and ODA has been found and characterized with IR, NMR, matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry, and elemental analyses. Films based on 2,2′,3,3′‐BTDA/TPEQ can only be obtained from corresponding polyimide (PI) solutions prepared by chemical imidization because those from their polyamic acids by thermal imidization are brittle. PIs from 2,2′,3,3′‐BTDA have lower inherent viscosities and worse thermal and mechanical properties than the corresponding 2,3′,3′,4′‐BTDA‐ and 3,3′,4,4′‐BTDA‐based PIs. PIs from 2,2′,3,3′‐BTDA and 2,3′,3′,4′‐BTDA are amorphous, whereas those from 3,3′,4,4′‐BTDA have some crystallinity, according to wide‐angle X‐ray diffraction. Furthermore, PIs from 2,2′,3,3′‐BTDA have better solubility, higher glass‐transition temperatures, and higher melt viscosity than those from 2,3′,3′,4′‐BTDA and 3,3′,4,4′‐BTDA. Model compounds have been prepared to explain the order of the glass‐transition temperatures found in the isomeric PI series. The isomer effects on the PI properties are discussed. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2130–2144, 2004
Diels–Alder reaction with anthracene and quinone derivatives on the dendritic periphery
Authors: Kim Chungkyun , Kim Hyojeong , Park Kyungrae 
Published: March 2004

AbstractDiels–Alder (DA) adducts including 24, 48, and 96 bicyclo end groups on the dendritic periphery were prepared by the reaction of anthracene on the dendrimers (first to fourth generation) and 1,4‐benzoquinone as well as 1,4‐naphtoquinone in boiled toluene. The structural information of DA adducts on the dendritic periphery was received from the hyperfine structural analysis by 1H NMR spectroscopy. The gel permeation chromatography of DA products revealed very low polydispersity values and decreased regular retention time according to increasing generation. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2155–2161, 2004
Microencapsulation of cholesteryl alkanoate by polymerization‐induced phase separation and its association with drugs
Authors: Kim Jin‐Woong , Lee Kwang‐Sup , Ju Hee‐Kyung , Ryu Jee‐Hyun , Han Sang‐Hoon , Chang Ih‐Seop , Kang Hak‐Hee , Oh Seong‐Geun , Suh Kyung‐Do 
Published: March 2004

AbstractA new microencapsulation technique is presented in which cholesteryl nonanoate (CN)/poly(methyl methacrylate) (PMMA) microcapsules are produced by the induction of phase separation between CN and PMMA within the droplets during the polymerization. The concentration of CN is the most important factor determining the final morphology of the microcapsules. For example, a polynuclear type is obtained at a low concentration (<20 wt %), a mononuclear type is obtained at a medium concentration (20–30 wt %), and an irregular phase is obtained at a high concentration (>40 wt %). To evaluate the effectiveness of the technique for stabilizing an unstable drug, we selected retinol (vitamin A) as a model drug and loaded it into the CN/PMMA microcapsules. We used a process called solute codiffusion, in which a fine solvent emulsion containing the retinol was diffused uniformly into the CN/PMMA microcapsules. The loading efficiency of retinol was predicted successfully with the aid of a thermodynamic equation. In the thermal stability test of retinol, we found that an effective association with the CN phase was the most important factor determining the limit of its molecular stability. The technique reported in this article has great potential for the microencapsulation of soft materials via a simple process and for the stabilization of unstable drugs. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2202–2213, 2004