Synthesis and chain extension of nitroxide‐terminated styrene–maleimide copolymers

Thermal radical copolymerization of styrene (S) and maleimide (MI) at 125°C in diglyme in the presence of 2,2,6,6‐tetramethylpiperidin‐1‐yloxyl radical (TEMPO) was studied. Mole fractions of maleimide in the feed, F_MI, varied in the range 0.1–0.9. A quasiliving reaction process proceeded yielding copolymers with a low polydispersity (M_w/M_n = 1.17–1.41). The found azeotropic composition, (F_MI)_A = 0.46, did not differ substantially from that (0.5) in the conventional radical S‐MI copolymerization. At a higher conversion or MI content in the feed, deactivation of the copolymer chains occurred. The obtained TEMPO‐terminated S‐MI copolymers readily initiated polymerization of styrene; chain extension of the macroinitiators took place, giving poly(S‐co‐MI)‐block‐poly(S) diblock copolymers. The synthesized copolymers containing S and MI units were characterized by elemental analysis, NMR spectroscopy, size‐exclusion chromatography, and differential scanning calorimetry. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1863–1868, 2004     

Synthesis and characterization of styrene–N-butyl maleimide copolymers using iniferters containing thiyl end groups

The radical homopolymerization of styrene or copolymerization of styrene (S) with N-butyl maleimide (I) initiated by tetraethylthiuram disulfide was used to prepare macroinitiators having thiyl end groups. The S–I copolymers from the feeds containing 30–70 mol % I showed approximately alternating composition. The rate of copolymerization and molecular weights decreased with increasing maleimide derivative concentration in the feed; homopolymerization of I alone did not proceed. The macroinitiators served for synthesis of further S–I copolymers. Using polystyrene macroinitiator and the S–I copolymer with thiyl end groups in the polymerization of S–I mixture and styrene, respectively, the copolymers containing blocks of both polystyrene and alternating S–I copolymer were obtained. The copolymerization of S–I mixture initiated with the S–I copolymer bearing thiyl end groups led to the extension of macroinitiator chains by the blocks of alternating copolymer. The presence of the blocks in the polymer products was corroborated using elemental analysis, size exclusion chromatography, and differential scanning calorimetry. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67: 755–762, 1998     

Synthesis and characterization of styrene–acrylic ester copolymers

Homopolymers and copolymers of styrene and different acrylic esters (i.e., acrylates) were synthesized by the free‐radical solution polymerization technique. Feed ratios of the monomers styrene and cyclohexyl acrylate/benzyl acrylate were 90 : 10, 75 : 25, 60 : 40, 50 : 50, 40 : 60 and 20 : 80 (v/v) in the synthesis of copolymers. All 6 homopolymerizations of acrylic ester synthesis were carried out in N,N(dimethyl formamide) except for the synthesis of poly(cyclohexyl acrylate) (PCA), where the medium was 1,4‐dioxane. Benzoyl peroxide (BPO) and azobisisobutyronitrile (AIBN) were used as initiators. The polymers synthesized were characterized by FTIR, ¹H‐NMR, ¹³C‐NMR spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and viscosity measurements. The reactivity ratios were determined by the Fineman–Ross method using ¹H‐NMR spectroscopic data. The reactivity ratios (r) for the copolymerization of styrene (r_S) with cyclohexyl acrylate (r_CA) were found to be r_S = 0.930 and r_CA = 0.771, while for the copolymerization of styrene with benzyl acrylate, the ratios were found to be r_S = 0.755 and r_BA = 0.104, respectively. The activation energies of decomposition (E_a) and glass‐transition temperature (T_g) for various homo‐ and copolymers were evaluated using TGA and DSC analysis. The activation parameters of the viscous flow, voluminosity (V_E) and shape factor (ν) were also computed for all systems using viscosity data. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1513–1524, 2001     

羧基官能团化的苹果酰亚胺衍生物的合成

用氨基酸与苹果酸酐直接反应,合成了两个含羧基官能团的苹果酰亚胺,为氨基酸氮端的保护以及含羧基官能团的酰亚胺类化合物的合成提供了一种直接、简便的新方法。     

Characterization of end‐functionalized styrene–butadiene–styrene copolymers and their application in modified asphalt

End amino, carboxylic acid, and hydroxyl functionalized styrene–butadiene–styrene (SBS) triblock copolymers were prepared with 1,5‐diazabicyclo[3.1.0]hexane, carbon dioxide, and epoxy ethane as capping agents, respectively. The effects of the end polar groups on the morphology and dynamic mechanical properties were investigated. Transmission electron microscopy images suggested that the group at the end of the polystyrene (PS) segment made the morphology of the PS domains disordered and incompact. Dynamic mechanical results showed that the storage and loss modulus increased after SBS was end‐functionalized. End amino and carboxylic acid groups improved the compatibility and storage stability of SBS‐modified asphalt. However, the effect of the end‐hydroxyl group on the improvement of the storage stability of SBS‐modified asphalt was not obvious. The differential scanning calorimetry analysis of SBS‐modified asphalt further showed that the compatibility and storage stability of SBS‐modified asphalt were improved by the attachment of amino or carboxylic acid groups through the anionic polymerization method. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 8–16, 2007     

Synthesis and characterization of functionalized syndiotactic polystyrene copolymers

Functionalized syndiotactic polystyrene copolymers were synthesized and characterized. The syndiotactic polystyrene copolymers, poly(styrene‐co‐4‐methylstyrene) (sPSMS), were prepared by styrene with 4‐methylstyrene with a metallocene/methylaluminoxane catalyst. In addition, grafted copolymers, chemically grafted with isoprene onto an sPSMS backbone [poly(styrene‐co‐4‐methylstyrene)‐g‐polyisoprene (sPSMS‐g‐PIP)] were synthesized by anionic grafting polymerization with a metallation reagent. In this study, we also examined the effect of the degree of functionalization (epoxidation) on the polymer structure of the sPSMS‐g‐PIP copolymers. Experimental results indicate that the crystallinity of the sPSMS‐g‐PIP copolymer was lower than that of the ungrafted sPSMS copolymer. Moreover, the epoxy‐containing sPSMS‐g‐PIP copolymer effectively increased the thermal stability more than did the sPSMS‐g‐PIP copolymer alone. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1038–1045, 2002     

Synthesis,characterization, and coordination behavior of copoly(styrene‐maleimide) functionalized with terpyridine

A maleimide functionalized terpyridine, 4′(4‐maleimidophenyl)‐2, 2′ : 6′, 2″‐terpyridine, was synthesized and copolymerized with styrene via radical polymerization. The synthesized monomer was characterized by CHN elemental analysis, FT‐IR, ¹H NMR, and Mass spectrometry. The structure of polymer was also confirmed by FT‐IR and UV‐Vis spectroscopy. The resulting polymer was soluble in chloroform and polar aprotic solvents, and showed an inherent viscosity of 1.5 dL/g in N,N‐dimethyl formamide at 25°C. The polymer solution in CHCl₃/methanol showed a metal‐ligand charge‐transfer band of 586 nm upon addition of Fe(II) ion, exhibiting that coordination between terpyridine units and Fe(II) had occurred. The thermal stability of polymer before and after complexation with Fe(II) was examined by thermogravimetric analysis. For polymer before complexation, the weight loss started at 180°C whereas for complexed polymer it started at 260°C, which demonstrates good thermal stability of complexed polymer. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis of styrene–isoprene A2B2 hetero-armed star copolymers

Styrene–isoprene A₂B₂ star copolymers having two arms of polystyrene and two of polyisoprene have been synthesised. Two routes have been followed. In the first, 2 moles of polydienyl lithium were coupled, without loss of carbanionic character, by reacting with 1 mole of 1,3-bis(1-phenylethenyl) benzene. The difunctional adduct was then used to initiate the polymerisation of styrene in the presence of a small amount of triethylamine which served to ensure a rapid crossover. In the second route, 2 moles of polystyrl lithium were coupled with 1 mol of SiCl₄ in benzene; no attendant formation of three-armed star was detected. Introduction of large excess of polyisoprenyl lithium, together with triethylamine as catalyst, generated the star which was isolated by fractional precipitation.     

Synthesis,characterization, and properties of two‐component amphiphilic polyoxyethylene–containing multiblock copolymers

Amphiphilic (oxyethylene–oxypropylene) and (oxyethylene–styrene) multiblock copolymers, both with high molecular weights, were synthesized by coupling poly(ethylene glycol) (PEG) with poly(propylene glycol) (PPG) or with telechelic dihydroxy polystyrene using 2,4‐toluene diisocyanate as a coupling agent, respectively. The polymerization conditions were investigated. The products were purified and characterized by IR, ¹H‐NMR spectroscopy, and membrane osmometry and identified as multiblock copolymers. Crystallinity of the two kinds of multiblock copolymers was determined by DSC. They showed good emulsifying properties. Their complexes with LiClO₄ showed high room‐temperature conductivities from 3 × 10⁻⁵ to 4 × 10⁻⁴ S/cm at 30°C. High molecular weight (oxyethylene–oxypropylene) multiblock copolymers, at a weight ratio of PEG/PPG = 6/4, behave like thermoplastic elastomers. The (oxyethylene–styrene) copolymer functions as a good compatibilizer for the blend of chlorohydrin rubber and polystyrene. An amount of only 3 wt %, based on the blend, is needed to increase the tensile strength of the blend almost sixfold. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1295–1301, 2005     

Synthesis and characterization of heat‐resistant N‐phenylmaleimide–styrene–maleic anhydride copolymers and application in acrylonitrile–butadiene–styrene resin

The heat‐resistant copolymer of N‐phenylmaleimide (NPMI)–styrene (St)–maleic anhydride (MAH) was synthesized in xylene at 125°C with di‐tert‐butyl diperoxyterephthalate as an initiator. The characteristics of the copolymer were analyzed by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy (¹H‐NMR and ¹³C‐NMR), gel permeation chromatography, and elemental analysis. The ¹³C‐NMR results show that the copolymer possessed random sequence distribution; this was also supported by the differential scanning calorimetry experiment, in which a single glass‐transition temperature (T_g) of 202.3°C was observed. The thermal stability and degradation mechanism of the copolymer were investigated by thermogravimetric analysis. Using the Kissinger equation and Ozawa equation, we proved a nucleation controlling mechanism with an apparent activation energy of 144 kJ/mol. Blends of acrylonitrile–butadiene–styrene with the NPMI–St–MAH copolymer with various contents were prepared with a twin‐screw extruder processes. The mechanical and thermal properties of the materials, such as the tensile and flexural strength, T_g's, and Vicat softening temperatures, were all enhanced with the addition of the modifier, whereas the melt flow index decreased. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Methyl methacrylate–N-chlorophenyl maleimide copolymers: Effect of structure on properties

The article describes the preparation of cast acrylic sheets by copolymerizing methyl methacrylate (MMA) with varying mole fractions of N-o-chlorophenyl maleimide (OC), N-m-chlorophenyl maleimide (MC), and N-p-chlorophenyl maleimide (PC) using benzoyl peroxide as an initiator. The effect of incorporation of varying mole fraction of N-chlorophenyl maleimides in poly(methyl methacrylate) backbone on the optical, physicomechanical, and thermal properties of cast acrylic sheets were evaluated. Vicat softening temperature, glass transition temperature (T_g) and thermal stability of the copolymers increased with an increase in the maleimide content. The solar transmittance and percentage of transmittance of the copolymer sheets having low mole fractions of N-chlorophenyl maleimides (i.e., 0.025–0.085) were found to be comparable with that of PMMA. Further increase in the comonomer content resulted in a decrease in the percentage of transmittance. Copolymer sheets having low mole fractions of N-chlorophenyl maleimides (0.025–0.108) have tensile strength comparable to that of PMMA, whereas the percentage of elongation decreased. Tensile modulus increased with increasing mole fraction of N-chlorophenyl maleimides. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 527–534, 1998     

Solubility behavior of amphiphilic sulfonated copolymers based on styrene–stearyl methacrylate and styrene–stearyl cinnamate

Amphiphilic polymers have found many applications, so many types of these copolymers have been prepared. Specifically, sulfonated polystyrene acts, for example, as a flocullant or dispersant of petroleum asphaltenes as a function of its hydrophilic–hydrophobic balance. However, when changing the sulfonation degree, looking for the best performance, the solubility also changes, and sometimes it is responsible for making the polymer unsuitable for any application. Therefor, this work investigates in detail the changes in the solubility range of copolymers based on styrene–stearyl methacrylate and styrene–stearyl cinnamate with different molar compositions and different sulfonation degrees. The copolymers were synthesized and characterized by ¹H‐NMR, Fourier transform infrared spectroscopy, and elemental analysis. In the range of compositions analyzed, with increasing content of long hydrocarbon chains, not only the displacement of the solubility in solvents with lower solubility parameter (δ), but also the broadening of the solubility range was observed. In general, the solubility was directly related to the sulfonic group content, but there appeared to be an influence of the randomness of the sulfonation reactions along the chains. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43112.     

Wood-fiber reinforcement of styrene–maleic anhydride copolymers

Styrene–maleic anhydride (SMA) copolymers containing either 7 or 14% maleic anhydride were filled with either pine flour or dry-process aspen fiber from a medium density fiberboard (MDF) plant. Material properties of the filled and unfilled SMA plastics were compared with those of aspen-fiber-filled and unfilled polystyrene (PS). The fiber-filled SMA composites were equivalent or superior to unfilled SMA in strength, stiffness, and notched Izod impact strength. Filled PS composites outperformed or matched the performance of filled SMA composites in the parameters tested. Unnotched Izod impact strength of filled polymers was generally inferior to that of the unfilled polymers. Water absorption from a 90% relative humidity exposure, a 24-h soak, and a 2-h boil showed mixed results when compared to the unfilled polymers. Dynamic mechanical analysis showed no change in glass transition temperature (T_g) after the addition of filler for either SMA or PS composites. The presence of the anhydride functionality on the polymer backbone did not appear to improve the strength of the composite. No evidence was found for chemical bond formation between the SMA and wood fiber. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1567–1573, 1998     

Compatibility effect of radiation‐grafting‐functionalized styrene–butadiene–styrene on polyamide 6/styrene–butadiene–styrene blends

Styrene–butadiene–styrene (SBS) was grafted with dibutyl maleate (DBM), methacrylic acid (MAA), or maleic anhydride (MAH) by ⁶⁰Co γ‐rays. The grafted SBS was blended with polyamide 6 (PA6). The compatibility of the PA6/SBS blends was studied with scanning electron microscopy and rheological measurements. The results showed significant improvement in the compatibility of PA6 blended with MAH‐ or MAA‐grafted SBS, with the former being more effective, whereas grafting DBM was ineffective in this respect. Mechanisms of the compatibility enhancement and ineffectiveness are discussed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Preparation,characterization, and some properties of ionomers from a sulfonated styrene–butadiene–styrene triblock copolymer without gelation

The conditions for the sulfonation of a highly unsaturated styrene–butadiene–styrene triblock copolymer (SBS) in cyclohexane containing a small amount of acetone with acetyl sulfate made by sulfuric acid and acetic anhydride without gelation were studied. After neutralization with metallic ions, the ionomers were characterized with IR spectrophotometry, dynamic mechanical analysis, and transmission electron microscopy. The melt flow, solution properties, and mechanical properties of the ionomers were studied. The results showed that gelation occurred during the sulfonation of SBS in cyclohexane at a 5–10% concentration without acetone, whereas in the presence of 5–10 vol % acetone, sulfonation proceeded smoothly without gelation. Transmission electron microphotographs of the lead ionomer indicated the presence of ionic domains. A dynamic mechanical spectrum showed the presence of three transition temperatures: ?82.9, 68, and 96.5°C. The melt viscosity of the ionomer increased with the sulfonate content. The melt viscosity of the different ionomers neutralized with different cations seemed to decrease with decreasing ionic potential for both monovalent cations and divalent cations The solution viscosity of the sodium‐sulfonated ionomer increased with increasing sulfonate content. The ionomer still behaved as a thermoplastic elastomer and showed better mechanical properties than the original SBS. The tensile strength of the different ionomers decreased as follows. For the monovalent cations, it decreased with decreasing ionic potentials: Li⁺ > Na⁺ > K⁺. For the divalent cations, it decreased with increasing ionic potentials: Pb²⁺ > Zn²⁺ > Mg²⁺. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1398–1404, 2005     

Porous structure and swelling properties of styrene–divinylbenzene copolymers for size exclusion chromatography

Small spherical particles of styrene–divinylbenzene copolymers have been synthesized by modified suspension polymerization. The effects of divinylbenzene (DVB) contents, dilution degree of the monomers and diluent composition on the porous structure and swelling properties of the copolymers were investigated. Toluene uptakes of macroporous copolymers were considered as a result of three contributions: filling of the fixed pores, expansion of the fixed or collapsed pores, and nuclei swelling and heptane uptakes as a result of the two first contributions. The increase of DVB content in the copolymers synthesized in presence of a solvating diluent (toluene) provoked a decrease on the nuclei swelling. The increase of dilution degree with solvating diluents changed the toluene and heptane uptakes, and when the diluent–copolymer affinity was reduced, the fixed pore volume increased. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:1257–1262, 1997     

Synthesis and properties of silicon-containing maleimide polymers based on N-(trimethylsilyl)maleimide

N-(Trimethylsilyl)maleimide (TMSMI) has been polymerized with various styrenic monomers (XSt) in the presence of a radical initiator to give high-molecular-weight, alternating copolymers in high yields. The copolymers P(TMSMI/XSt) have high glass transition temperatures above 200°C and thermal decomposition temperatures in the range 320–360°C. The thermal and acidolytic deprotection of trimethylsilyl (TMS) groups of TMSMI units in the copolymers have been investigated. UV irradiation and subsequent heating of a film of P(TMSMI/t-BOCSt) containing a photoacid generator resulted in deprotection of the protecting groups by the photogenerated acids, thereby causing a significant change in solubility of the polymer. Thus positive image patterns were obtained with P(TMSMI/t-BOCSt) by photolithographic processes. © 1998 Society of Chemical Industry     

N-苯基马来酰亚胺改性酚醛树脂的合成及其结构性能

采用滴加苯酚的方式合成了N-苯基马来酰亚胺改性酚醛树脂（PPMF）, 考察了N-苯基马来酰亚胺（PMI）参与酚醛缩聚反应的转化程度和树脂黏度特性的变化规律.发现延长苯酚滴加时间能提高PMI参与共缩聚反应的竞争能力和转化率;随着回流反应时间的增加,PMI转化率增加,树脂的黏度也随之增大;较高的反应温度或较大的PMI用量均会导致PMI转化率的显著下降.利用核磁、红外和元素分析等表征了改性酚醛树脂的结构及组成,确定N-苯基马来酰亚胺已共缩合于酚醛树脂中,其中PMI含量可达33％左右.利用DSC和TGA研究了N-苯基马来酰亚胺改性酚醛树脂的固化特性和耐热性能,发现PPMF树脂经历了两个固化阶段, 第一阶段是少量羟甲基的缩合, 第二阶段为马来酰亚胺的双键打开自交联形成. PPMF树脂固化产物的耐热性能优于传统的热塑性酚醛树脂.