Interpenetrating polymer networks based on poly(chloroprene) and poly(carbonate-urethane)

Simultaneous interpenetrating polymer networks (SIN's) of poly(chloroprene) (CR) and poly(carbonate-urethane) (PCU) were prepared and characterized. The effect of composition on the phase morphology of full IPN's of CR/PCU has been studied by DSC and SEM. A single phase morphology of IPN's has achieved when the content of CR component is below 50 wt %. The microphase separation of the component networks in the IPN's occurred in samples whose weight percentage of the CR component was 50% and higher. © 1993 John Wiley & Sons, Inc.     

Interpenetrating polymer networks of poly(carbonate-urethane) and polyvinyl pyridine

Simultaneous interpenetrating polymer networks (IPN's), pseudo IPN's, and liner blends of aliphatic poly(carbonate-urethane) (PCU) and polyvinyl pyridine (PVP) have been prepared and characterized by DSC, DMA, and TEM. The full IPN's of PCU and PVP had a single phase morphology only above 50 wt % PCU, as determined by both DSC and DMA and confirmed by transmission electron microscopy (TEM). However, in both pseudo IPN's of PCU and PVP and in their linear blends there exist multiple glass transitions and melting points seen by DSC and DMA indicating phase incompatibility. The full IPN's exhibited superior ultimate mechanical properties and solvent resistance as compared to the pseudo IPN's, liner blends, and the pure crosslinked PCU and PVP networks.     

Interpenetrating polymer networks of poly(carbonate-urethane) and polymethyl methacrylate

We report the synthesis and characterization of interpentrating polymer networks (IPN's), pseudo INPN's, and blends of urethane-containing aliphatic polycarbonates (PCU) and polymethyl methacrylate (PMMA). The simultaneous full IPN's of PCU's and PMMA over the whole composition range have only one T_g, as determined by DSC and DMA which, together with transmission electron microscopy observations, suggest a single phase morphology even though the linear chain blends are completely immiscible. The full IPN's exhibit a maximum tensile strength at a certain composition, and superior solvent and heat resistance as compared to the pseudo IPN's, linear blends, and the pure crosslinked PCU's and PMMA.     

Preparation and properties of polyurethane networks based on α,ω-difunctional poly(hexafluoropropylene oxide)

Poly(hexafluoropropylene oxide), poly(HFPO), networks were prepared from functional polymers by end linking via urethane groups. The prepolymers were characterized by NMR spectroscopy and GPC. The networks were characterized by determination of the number of network chains from the shear modulus, and were snown to contain both trifunctional crosslinks and difunctional links. The properties of the networks were investigated by a range of techniques. Compared with fully-fluorinated networks formed via triazine cross-links, investigated previously, the urethane-linked networks were more readily prepared but were poorer elastomers, were less thermally stable, and were less resistant to swelling by common polar solvents. © 1995 John Wiley & Sons, Inc.     

Synthesis and physical properties of poly(urethane)s using vicinal diols derived from acrylate and styrene monomers

We describe the utilization of four kinds of diol derivatives, representing structural similarity to the well‐known and commercially available vinyl monomers such as acrylate, acrylamide, styrene, and N‐substituted maleimide. The vinyl monomers are readily converted by dihydroxylation reaction to afford the vicinal diol. The synthesis of poly(urethane)s was performed by the reaction of the vicinal diol with two model diisocyanates, including methylene diphenyl isocyanate (MDI) and hexamethylene diisocyanate (HDI) in the presence of dibutyltin dilaurate to form a series of poly(urethane)s, and the effect of vicinal diol containing a side chain inherited from vinyl monomers on their thermal and mechanical properties was investigated using thermogravimetric analysis, differential scanning calorimetry, and tensile test. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 799–805     

Interpenetrating polymer networks of poly(dimethyl siloxane–urethane) and poly(methyl methacrylate)

Simultaneous IPNs of poly(dimethyl siloxane-urethane) (PDMSU)/poly(methyl methacrylate) (PMMA) and related isomers have been prepared by using new oligomers of bis(β-hydroxyethoxymethyl)poly(dimethyl siloxane)s (PDMS diols) and new crosslinkers biuret triisocyanate (BTI) and tris(β-hydroxylethoxymethyl dimethylsiloxy) phenylsilane (Si-triol). Their phase morphology have been characterized by DSC and SEM. The SEM phase domain size is decreased by increasing crosslink density of the PDMSU network. A single phase IPN of PDMSU/PMMA can be made at an M_c = 1000 and 80 wt % of PDMSU. All of the pseudo- or semi-IPNs and blends of PDMSU and PMMA were phase separated with phase domain sizes ranging from 0.2 to several micrometers. The full IPNs of PDMSU/PMMA have better thermal resistance compared to the blends of linear PDMSU and linear PMMA. © 1993 John Wiley & Sons, Inc.     

Methacrylate modified clays and their polystyrene and poly(methyl methacrylate) nanocomposites

Two methacrylate‐modified clays have been prepared and used to produce nanocomposites of polystyrene and poly(methyl methacrylate) by in situ polymerization. These nanocomposites have been characterized by X‐ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), cone calorimetry and the evaluation of mechanical properties. When the clay contains only a single methacrylate unit, the styrene system is exfoliated but methacrylate is intercalated. When two methacrylate units are present on the cation of the clay, both systems are exfoliated. TGA data show that the thermal stability of all the nanocomposites is improved, as expected. The relationships between the fire properties and nanostructure of the nanocomposites are complicated, as shown by cone calorimetry. The conclusions that one may reach using cone calorimetry do not completely agree with those from XRD and TEM. The evaluation of mechanical properties shows an increase in Young's modulus for all nanocomposites along with a decrease in elongation; tensile strength is decreased for methacrylate nanocomposites but increased for styrenics systems. Copyright © 2004 John Wiley & Sons, Ltd.     

Thermal and dynamic mechanical properties of poly(propylene carbonate)

Summary Thermal and dynamic mechanical properties of carbon dioxide and propylene oxide alternative copolymer, poly(propylene carbonate) (PPC), and the end-capped PPC with maleic anhydride were investigated by means of TG and DMA. A master curve of the storage modulus vs. frequency can be deduced from the isochronal curves. Physical parameters of both plain and MA end-capped PPC were discussed. The results showed that for maleic anhydride (MA) end-capping PPC, an improvement of its thermal stability and mechanical properties accompanied with some modifications of the viscoelastic behavior were obtained.     

Poly(silmethylene)-based polymer blends. II. Synthesis and characterization of poly(diphenylsilmethylene)/poly(methylphenylsilmethylene) blends1

Poly(diphenylsilmethylene) (PDPSM)/poly(methylphenylsilmethylene) (PMPSM) binary polymer blends were synthesized by in situ ring-opening polymerization of 1,1,3,3-tetraphenyl-1,3-disilacyclobutane in PMPSM. Three catalytic methods as well as a noncatalytic method were employed. Radical initiators such as an organic peroxide or azo-compound proved to be the effective catalysts in addition to copper compounds. Blend samples were characterized in detail by DSC, dynamic mechanical analysis, solvent extraction, and microscopic observation to clarify the relationship between the preparative method and the properties of these polymer blends. It is strongly suggested that a part of PMPSM is converted into an insoluble form via formation of PDPSM–PMPSM block or graft copolymers in the case of the in situ copper-catalyzed polymerization in xylene. The formation of block or graft copolymers is also suggested for samples prepared by the in situ bulk polymerization in the presence of a radical initiator. However, PMPSMs simultaneously underwent molecular weight decrease and insolubilization probably due to polymer chain scission and crosslinking, respectively, when the latter method was employed using PMPSM with very high molecular weight. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1431–1442, 1997     

Photocrosslinked hydrogels based on copolymers of poly(ethylene glycol) and lysine

A group of new, water-soluble poly(ether-urethane)s, derived from poly(ethylene glycol) and the amino acid L -lysine, provide pendent carboxylic acid groups along the polymer backbone at regular intervals. The carboxylic acid groups were utilized for the attachment of acrylate and methacrylate pendent chains (hydroxyethyl acrylate, hydroxyethyl methacrylate, aminoethyl methacrylate, and aminoethyl methacrylamide), leading to functionalized polymers. The pendent chains were attached via ester and/or amide bonds having different degrees of hydrolytic stability. The attachment reactions proceeded with high yields (up to 95%). The functionalized polymers were subsequently photopolymerized (UV irradiation) to obtain crosslinked hydrogels. Crosslinked membranes with the highest degree of mechanical strength were obtained when the crosslinking reaction was performed in dioxane with benzoin methyl ether (0.1 wt %) as the initiator. the crystallinity, thermomechanical properties, and hydrolytic stability of the crosslinked membranes were studied. All membranes were transparent and highly swellable (equilibrium water content: 64–88%). The tensile strength in the swollen state ranged from 0.15 to 1.09 MPa. Under physiological conditions (phosphate buffered water, 0.1M, pH 7.4, 37°C) the hydrolytic stability of the hydrogels varied depending on the bonds used in the attachment of the acrylate pendent chains: Hydrogels with hydroxyethyl acrylate pendent chains dissolved within 30 days, while hydrogels containing aminoethyl methacrylamide pendent chains remained unchanged throughout a 30 day period. Using high molecular weight FITC-dextrans as model compounds, complete release from the swollen hydrogels required between 60 and 150 h. Overall, the evaluation of poly(ethylene glycol)-lysine derived, photocrosslinked hydrogels indicated that these materials provide a range of potentially useful properties. © 1994 John Wiley & Sons, Inc.     

Synthesis,characterization, and comparison of properties of new fluorinated poly(arylene ether)s containing phthalimidine moiety in the main chain

Four new poly(arylene ether)s have been prepared by the reaction of N‐phenyl‐3,3‐bis(4‐hydroxyphenyl)phthalimidine (PA) with four different perfluoroalkylated monomers namely 1,3‐bis(4′‐fluoro‐3′‐trifluoromethyl benzyl) benzene, 4,4′‐bis(4′‐fluoro‐3′‐trifluoromethyl benzyl) biphenyl, 2,6‐bis(4′‐fluoro‐3′‐trifluoromethyl benzyl) pyridine, and 2,5‐bis(4′‐fluoro‐3′‐trifluoromethyl benzyl) thiophene. The poly(arylene ether)s were characterized by different spectroscopic, thermal, mechanical, and electrical techniques. The poly(arylene ether) containing quadriphenyl unit in the main chain showed very high glass transition temperature of 291°C and outstanding thermal stability upto 556°C for 10% weight loss under a 4:1 nitrogen:oxygen mixture. The polymers were soluble in a wide range of organic solvents. Transparent thin films of these polymers exhibited tensile strengths upto 75 MPa and elongation at break upto 32%. The films of these polymers showed low water absorption of 0.26%. Copyright © 2009 John Wiley & Sons, Ltd.     

Co‐poly(aryl ether sulfone)s containing phthalimidine moiety in the main chain

Several new co‐poly(arylene ether sulfone)s have been prepared by the reaction of 4,4′‐fluorodiphenyl sulfone (FDS) with different bisphenols namely 4,4′‐isopropylidenediphenol (BPA), 4,4′‐hexafluoroisopropylidenediphenol (6F‐BPA), and N‐phenyl‐3,3‐bis(4‐hydroxyphenyl)phthalimidine(PA). The homo‐poly(arylene ether sulfone)s are named as 1a, 2a, and 3a. The copolymers namely 2b, 2c, 2d and 3b, 3c, 3d have been prepared, respectively, on reaction of FDS with BPA or 6F‐BPA using different molar ratios of PA such as 25, 50, and 75. The poly(aryl ether sulfone)s 1a containing PA unit in the main chain showed a very high glass transition temperature of 280°C and an outstanding thermal stability up to 510°C for 5% weight loss under synthetic air. Depending on the mole% of PA, the glass transition temperatures of the copolymers can be varied. The polymers were soluble in a wide range of organic solvents. Transparent thin films of these polymers exhibited tensile strengths upto 84 MPa and Young's modulus up to 3.16 GPa. The films of these polymers showed low water absorption of 0.24%. Copyright © 2009 John Wiley & Sons, Ltd.     

Synthesis and characterization of thianthrene-containing poly(benzoxazole)s

New thioether- and thianthrene-containing poly(benzoxazole)s (PBOs) were synthesized from 4,4′-thiobis[3-chlorobenzoic acid] and thianthrene-2,7- and -2,8-dicarbonyl chlorides with commercially available bis-o-aminophenols. Polymers were prepared via solution polycondensation in poly(phosphoric acid) at 90–200°C. Transparent PBO films were cast directly from polymerization mixtures or m-cresol. The films were flexible and tough. Non-fluorinated PBOs were soluble only in strong acids and AlCl₃/NO₂R systems by forming complexes with the benzoxazole heterocycle Glass transition temperatures ranged from 298–450°C, and thermogravimetric analysis showed good thermal stabilities in both air and nitrogen atmospheres. © 1995 John Wiley & Sons, Inc.     

聚N-异丙基丙烯酰胺接枝聚苯乙烯高分子刷的构象

当长链高分子高密度接枝到一个表面上时,由于分子链间的相互作用使得接枝的高分子链扩张而形成伸直链的构象,这种形态被称为高分子刷.     

共混方法对聚氯乙烯/聚丙撑碳酸酯相容性影响

本文分别用溶液法和熔融法制得聚氯乙烯（PVC）与聚丙撑碳酸酯（PPC）共混试样，用DSC证明PVC／PPC共混物不相容，但它们不相容的程度受分子量、共混比例等因素的影响，并根据玻璃化转变温度（Tg）计算出溶液共混试样PPC富相中PVC的重量百分含量。NBR／PPC弹性体作偶联剂对PVC／PPC共混体系具有较好的增容作用，共混物中PPC的用量及分子量对共混体系性能有一定的影响。     

Influence of the soft segment length on the properties of water‐cured poly(carbonate‐urethane‐urea)s

Poly(carbonate‐urethane‐urea)s (PCUU) based on oligocarbonate diols (M_n ≈ 2000) with different length of the hydrocarbon chain as soft segments were synthesized and investigated. Carbonate oligomerols were obtained in a two‐step method from dimethyl carbonate (DMC) and linear α,ω‐diols (1,4‐butanediol, 1,5‐pentanediol, 1,6‐hexanediol, 1,9‐nonanediol, 1,10‐dekanediol and 1,12‐dodecanediol). Oligo(trimethylene carbonate) diol was synthesized using ring‐opening polymerization of trimethylence carbonate. PCUUs were obtained by prepolymer method using isophorone diisocyanate (IPDI) and water as a chain extender. Changes in polymers properties with increase of methylene group number between carbonate linkages were investigated by differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), tensile strength and hardness measurements. The thermal stability was also analyzed by means of thermogravimetric analysis (TGA). Based on FTIR analysis influence of methylene groups number between carbonate linkages on phase separation and concentration of allophanate and biuret groups in the samples were investigated. The obtained poly(carbonate‐urethane‐urea)s exhibited very good mechanical properties. Tensile strength and elongation at break were 40 MPa and 400–600%, respectively, depending on the oligocarbonate used. Copyright © 2014 John Wiley & Sons, Ltd.     

Characterization and degradation of poly(methylphenylsiloxane)–poly(methyl methacrylate) interpenetrating polymer networks

Poly(methylphenylsiloxane)–poly(methyl methacrylate) interpenetrating polymer networks (PMPS–PMMA IPNs) were prepared by in situ sequential condensation of poly(methylphenylsiloxane) with tetramethyl orthosilicate and polymerization of methyl methacrylate. PMPS–PMMA IPNs were characterized by infrared (IR), differential scanning calorimetry (DSC), and ²⁹Si and ¹³C nuclear magnetic resonance (NMR). The mobility of PMPS segments in IPNs, investigated by proton spin–spin relaxation T₂ measurements, is seriously restricted. The PMPS networks have influence on the average activation energy E_a,av of MMA segments in thermal degradation at initial conversion. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1717–1724, 1999     

Improvement of the thermal stability of cluster‐crosslinked polystyrene and poly(methyl methacrylate) by optimization of the polymerization conditions

The polymerization conditions for polystyrene and poly(methyl methacrylate) crosslinked by 0.5 mol % of the cluster Zr₆O₄(OH)₄(methacrylate)₁₂ were optimized by applying a step polymerization procedure. The onset of thermal decomposition was thus increased up to about 50° for polystyrene and about 110° for poly(methyl methacrylate). The increase in thermal stability correlated with a higher char yield. The glass transition temperatures were also increased by about 15°. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6586–6591, 2005     

Synthesis and thermal behavior of poly(ethylene oxide) poly(N‐substituted urethane)

Poly(N‐substituted urethane)s with an alkyl or ligo(ethylene oxide) monomethyl ether side chain were synthesized by the reaction operating in the following two‐step process: first, by metalation of the starting polymer with potassium tertiary butoxide (t‐BuOK) and then by treatment of the obtained urethane polyanion with tosylate in dimethyl sulfoxide. The thermal properties of poly(ethylene oxide) poly(N‐substituted urethane) (N‐sub PEOPU) were investigated in view of the N‐substitution degree and properties of the substituent. The chemical structures were characterized by Fourier transform infrared, ¹H NMR, and ¹³C NMR spectroscopies. DSC and thermogravimetric analysis (TGA) were used to investigate the thermal properties of N‐sub PEOPUs. As the degree of N‐methylation increased, the glass‐transition temperature (T_g) of the N‐sub PEOPUs linearly decreased from 6 to ?29 °C, and the weight‐loss temperature of 5% (T) from TGA in air increased from 278 to 360 °C. In the fully N‐substituted PEOPUs, the behavior of the thermal decomposition of the PEOPU that was processed in two stages was changed to one‐step decomposition in the temperature range of 360–440 °C. The T_g was shifted to a lower temperature with an increasing length of the substituent in N‐sub PEOPU. Improvement of the thermal stability by N‐substitution was more significant in N‐alkyl PEOPU than in N‐ethoxylate PEOPU. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 4129–4138, 2001