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     

橡胶增韧苯乙烯与马来酸酐共聚物的方法

对增韧无规苯乙烯/马来酸酐共聚物(SMA)的方法作了分类,并对国内外SMA研究方面的进展作了分析。可以认为,橡胶增韧无规SMA,无论从耐热、冲击性能,还是从价格/性能比而言,是一类值得开发的高分子材料。以不同品种橡胶(如乙丙橡胶、苯乙烯-丁二烯-苯乙烯和丁基橡胶等)作增韧剂,通过不同的增韧方法,可以达到不同的增韧效果,满足不同的需求。     

Synthesis and characterization of alkali‐modified styrene‐maleic anhydride copolymer for dispersion of TiO2

A copolymer of styrene and maleic anhydride was synthesized by free radical polymerization at 80°C using N,N‐dimethylformamide (DMF) as solvent and benzoylperoxide as initiator. The monomer feed ratio of styrene to maleic anhydride was varied in the range of 1 : 1 : to 3 : 1. The polymer yield was found to decrease with increase in styrene in the feed. The molecular weight of copolymers which were formed by taking styrene to maleic anhydride ratio of 1 : 1, 2 : 1, and 3 : 1, as determined by Ostwald Viscometery were about 1862, 2015, and 2276 respectively. The acid values of abovementioned three copolymers were found to be 480, 357, and 295, respectively. The typical viscosity values of 20% solids in ammonical solution of copolymers formed by taking feed ratios of Sty : MAn as 1 : 1 and 2 : 1 were 26 and 136 cp, respectively. For the feed ratio 3 : 1, a gel was formed. The synthesized copolymers were hydrolyzed by alkalis, namely, NaOH, KOH, and NH₄OH. The dispersing ability of hydrolyzed styrene‐maleic anhydride (SMA) copolymers for dispersion of titanium dioxide was studied. The modified SMA copolymers were found to be effective dispersants for TiO₂. Among the three alkalis studied, the Sodium salts of SMA were found to give better dispersion. The copolymer having a 1 : 1 feed ratio showed the best dispersing ability for TiO₂ particles among the three ratios studied. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3194–3205, 2007     

Kinetics and simulation of the imidization of poly(styrene‐co‐maleic anhydride) with amines

The imidization of poly(styrene‐co‐maleic anhydride) with amines may improve some of its end‐use properties. The objective of this study was to examine the mechanism and kinetics with aniline (ANL) as an amine of the preparation of poly(styrene‐co‐N‐phenyl maleimide). The reaction was carried out in a tetrahydrofuran solution at 25–55°C and in an ethylbenzene solution at 85–120°C. The extent of the reaction was determined by conductance titration, a new and simple method. Two consecutive reactions were involved in the imidization: ring opening to produce an acido‐amide group and ring closing to form a corresponding imide group. The imidization rate was greatly influenced by the reaction temperature and the molar ratio of ANL to the anhydride. A model for the imidization kinetics over a wide range of reaction temperatures and concentration ranges was developed and validated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2744–2749, 2006     

Compatibilization and characterization of blends of styrene–maleic anhydride copolymer with modified polyethylenes

Potentially reactive blends of styrene–maleic anhydride (SMAH) with ethylene/methyl acrylate/glycidyl methacrylate (E‐MA‐GMA) and nonreactive blends of SMAH with ethylene/methyl acrylate (E‐MA) were produced in a Brabender batch mixer and in a corotating twin‐screw extruder. The products were characterized in terms of rheology, morphology, and mechanical properties to understand the reaction characteristics between anhydride/epoxy functional groups. Storage modulus, G′, loss modulus, G″ and complex viscosity, η* of the reactive blends were higher than those of nonreactive ones. At 25% E‐MA‐GMA content, maximum in η* was obtained for the reactive blends. The reactive blends showed finer morphology than the nonreactive ones at all concentrations studied. Mechanical characterization showed that reactive SMAH/E‐MA‐GMA blends had higher tensile strength, % strain at break, and tensile modulus than the nonreactive blends for all corresponding modified polyethylene contents. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 790–797, 2001     

Preparation of well‐defined block copolymer having one polystyrene segment and another poly(styrene‐alt‐maleic anhydride) segment with RAFT polymerization

Block copolymers, polystyrene‐b‐poly(styrene‐co‐maleic anhydride), have been prepared by reversible addition‐fragmentation chain transfer (RAFT) polymerization technique using three different approaches: 1‐phenylethyl phenyldithioacetate (PEPDTA) directly as RAFT agent, mediated polystyrene (PS) block as the macromolecular PS‐RAFT agent and mediated poly(styrene‐maleic anhydride) (SMA) block with alternating sequence as the macromolecular SMA‐RAFT agent. Copolymers synthesized in the one‐step method using PEPDTA as RAFT agent possess one PS block and one SMA block with gradient structure. When the macromolecular RAFT agents are employed, copolymers with one PS block and one alternating SMA block can be produced. However, block copolymers with narrow molecular weight distribution (MWD) can only be obtained using the PS‐RAFT agent. The MWD deviates considerably from the typical RAFT polymerization system when the SMA is used as the RAFT agent. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Rheological behavior of styrene‐maleic anhydride/polyol blends obtained through reactive processing

The condensation reaction of styrene‐maleic anhydride copolymer (SMAH) with polytetramethylene ether glycol (PTMEG) in the presence or absence of a hydrated zinc acetate catalyst was studied in a batch mixer. As a control, pure SMAH and an SMAH/catalyst blend were also subjected to the same processing conditions. The reaction characteristics of the blends were investigated by Fourier transform infrared spectroscopy (FTIR) and thermal and rheological analysis. FTIR analysis of the SMAH/PTMEG blend indicated ester formation. The addition of zinc acetate and/or PTMEG to SMAH decreased the glass transition temperature of pure SMAH. Oscillatory shear properties of storage modulus, G′, loss modulus, G″, and complex viscosity, η*, were measured. The SMAH/PTMEG/zinc acetate blend had higher G′, G″, and η* than the blend without the zinc acetate catalyst. The parameters of the relaxation spectra were calculated by using the experimental oscillatory data and the generalized Maxwell model. Zero shear viscosity and the mean relaxation time increased with addition of zinc acetate and/or PTMEG to SMAH as a result of chain extension/branching reactions. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2615–2623, 2002     

Variations of the glass‐transition temperature in the imidization of poly(styrene‐co‐maleic anhydride)

The imidization of poly(styrene‐co‐maleic anhydride) (SMA) was conducted, and the glass‐transition temperatures (T_g's) of the resulting products were measured with differential scanning calorimetry. The contributions from functional groups of maleic anhydride, N‐phenylmaleamic acid, and N‐phenylmaleimide to T_g were examined. T_g increased in the order of SMA < styrene–N‐phenyl maleimide copolymer < styrene–N‐phenyl maleamic acid copolymer and followed the Fox equation. T_g of the imidized products of SMA could be controlled by the conversions of both ring‐opening and ring‐closing reactions. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2418–2422, 2007     

Synthesis of ultrafine poly(styrene‐maleic anhydride) and polystyrene fibers by electrospinning

Fiber formation from atactic polystyrene (aPS) and alternating poly(styrene‐maleic anhydride) (PSMA) synthesized by free radical polymerization (AIBN, 90°C, 4 h) were investigated by electrospinning from various solutions. aPS was soluble in dimethylformamide (DMF), tetrahydrofuran (THF), toluene, styrene, and benzene, whereas PSMA was soluble in acetone, DMF, THF, dimethylsulfoxide (DMSO), ethyl acetate, and methanol. aPS fibers could be electrospun from 15 to 20% DMF and 20% THF solutions, but not from styrene nor toluene. PSMA, on the other hand, could be efficiently electrospun into fibers from DMF and DMSO at 20 and 25%, respectively. Few PSMA fibers were, however, produced from acetone, THF, or ethyl acetate solutions. Results showed that solvent properties and polymer–solvent miscibility strongly influenced the fiber formation from electrospinning. The addition of solvents, such as THF, generally improved the fiber uniformity and reduced fiber sizes for both polymers. The nonsolvents, however, had opposing effects on the two polymers, i.e., significantly reducing PSMA fiber diameters to 200 to 300 nm, creating larger and irregularly shaped aPS fibers. The ability to incorporate the styrene monomer and divinylbenzene crosslinker in aPS fibers as well as to hydrolyze PSMA fibers with diluted NaOH solutions demonstrated potential for post‐electrospinning reactions and modification of these ultrafine fibers for reactive support materials. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Liquid crystallization of poly(styrene‐co‐maleic anhydride) induced by intermolecular hydrogen bonds

The liquid crystallization of general polymer (GP) with maleic anhydride in the main chain has been realized through molecular recognition and self‐assembly based on intermolecular hydrogen bonds. Poly[styrene‐co‐(N‐4‐carboxylphenyl)maleimide] (SMIBA) was synthesized by imidization and dehydration of Poly(styrene‐co‐maleic anhydride) (SMA) with p‐aminobenzoic acid (ABA) for use as an H‐bonded donor polymer. 4‐Methoxy‐4′‐stilbazole (MSZ) and 4‐nitro‐4′‐stilbazole (SZNO₂) were prepared as an H‐bonded acceptor. SMIBA was complexed with MSZ or SZNO₂ by slow evaporation from pyridine solution to form a self‐assembly, which exhibits the mesophase, while neither of the individual components is mesogenic. The phase diagrams of a variety of mixtures between of SMIBA and stilbazoles have been established using DSC and POM. They show complete miscibility and high thermal stability of the liquid crystalline phase over the whole composition range. The tuning of liquid crystalline properties was achieved by changing the composition of the mixture and involving it with a mixture of SZNO₂ and MSZ. IR measurements strongly support the existence of an H‐bonded complex between the carboxylic acid of SMIBA and the pyridine group of stibazoles. Unlike conventional side‐chain liquid crystalline polymer (SLCP), supramolecular SLCP with a lower molecular weigh polymeric donor has higher thermal stability of the liquid crystalline phase due to the microphase separated in the hydrogen bonding case. Liquid crystallization of GP, such as SMA, induced by hydrogen bonds, offers a new route to prepare functional material with controlled molecular architecture from readily accessible and simpler precursors. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 97–105, 1999     

Preparation and characterization of polyurethane microcapsules containing n‐octadecane with styrene‐maleic anhydride as a surfactant by interfacial polycondensation

A series of polyurethane microcapsules containing a phase change material (PCM) of n‐octadecane was successfully synthesized by an interfacial polymerization in aqueous styrene‐maleic anhydride (SMA) dispersion with diethylene triamine (DETA) as a chain extender reacting with toluene‐2,4‐diisocyanate (TDI). The average diameter of microPCMs is in the range of 5–10 μm under the stirring speed of 3000–4000 rpm. Optical and SEM morphologies of microPCMs had ensured that the shell was regularly fabricated with the influence of SMA. FTIR results confirmed that the shell material was polyurethane and the SMA chains associated on core material reacted with TDI forming a part of shell material. The shell thickness was decreasing in the range of 0.31–0.55 μm with the molar ratio of DETA/TDI from 0.84 to 1.35 and the weight of core material increasing from 40 to 80% (wt %). By controlling the weight ratio of PCM as 40, 50, 60, 70, and 80% in microPCMs, it was found using DSC that the T_m and T_c of microPCMs were in the range of 29.8–31.0^oC and 21.1–22.0°C and an obvious phase change had been achieved nearly the same temperature range of that of PCM. The results from release curves of microPCM samples prepared by 1.4, 1.7, and 2.0 g of SMA indicated the release properties were affected by the amount of the dispersant, which attributed to the emulsion effect and shell polymerization structure. The above results suggest that the shell structure of microPCMs can be controlled and the properties of microPCMs determined by shell will perform proper practical usage. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4996–5006, 2006     

Blends of acrylonitrile–butadiene–styrene/waste poly(ethylene terephthalate) compatibilized by styrene maleic anhydride

Waste poly(ethylene terephthalate) (PET) from thin bottles was blended with acrylonitrile–butadiene–styrene (ABS) copolymer in different proportions, up to 10 wt %. Styrene maleic anhydride (SMA) copolymer was used as a compatibilizer. The tensile strength and heat deflection temperature of the blend were higher than that of virgin ABS. Flexural modulus remained unaffected, although a slight decrease in impact property was observed. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2593–2599, 2001     

Surface pattern in thin poly(styrene–maleic anhydride) films

Monodispersed poly(styrene–maleic anhydride) alternating copolymer (SMA) is synthesized through radical polymerization, and characterized by GPC, DSC, FT-IR and ¹H NMR spectra. The mole fraction, χ, of styrene in the copolymer is 0.51, determined from integrated ¹H NMR spectrum, this value is consistent with the alternating structure. FT-IR spectra show that maleic anhydride moieties on the backbone chains hydrolyze in a THF solution containing water, and HCl can accelerate the hydrolysis process. Atomic force microscopy reveals that well-arrayed and uniform-sized holes formed in thin SMA films on single crystal silicon wafer substrates spin-cast from the THF solutions containing HCl. HCl can also influence hydrogen bonding between the carboxylic acid groups in the THF solution, which is crucial for the formation of holes in the thin films. The volatilization process in the spin-casting is divided into two stages, THF and water volatilization. The formation of holes is interpreted as the trace of water droplets emulsified by the hydrolyzed SMA in the second stage, i.e. water volatilization. Results also indicate that there are both mobile and bound water populations in the solution, and that the bound water is responsible for the hole or valley pattern of these thin films.     

Synergistic effect of dual rubber system in toughening styrene maleic anhydride copolymers

Styrene maleic anhydride (SMA) copolymers were toughened by blending with two distinctly different rubber modifiers: styrene‐butadiene‐styrene (SBS) block copolymer and methacrylated butadiene‐styrene emulsion‐made graft copolymer (MBS). The modifiers were used both individually and in combination for the examination of their roles in toughening SMA. SMA was miscible with poly(methylmethacrylate) shell of MBS, whereas it was partially miscible with the polystyrene (PS) phase of SBS. When 40–50% of SBS was used in blends, the PS phase of SBS became immiscible with SMA. SBS did not improve the Izod impact strength of SMA appreciably. A prominent synergistic toughening effect was experimentally observed when SBS and MBS were used in combination in brittle SMA. This effect may be attributed to the fact that the large SBS particles initiate crazes and small MBS particles with good adhesion to SMA matrix improve the ligament thickness, which may play a critical role in craze growth and termination. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2260–2267, 2003     

Grafting of maleic anhydride onto styrene–butadiene–styrene triblock copolymer using supercritical CO2 as a swelling agent

Grafting of maleic anhydride (MA) onto styrene–butadiene–styrene triblock copolymer (SBS) was carried out by free radical polymerization using supercritical carbon dioxide (SC CO₂) as a solvent of MA and swelling agent of SBS. The effect of various factors such as monomer concentration, initiator concentration, SC CO₂ pressure, and reaction time on grafting ratio was studied. SBS and the product (SBS‐g‐MA) were characterized by Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). GPC data showed that the molecular weight of SBS‐g‐MA is bigger than that of SBS. DSC testing indicated that the glass transition temperature (T_g) of SBS‐g‐MA is higher than that of SBS. By SEM photo, we can observe that some particles which contain more oxygen atom grew out from the surface of SBS‐g‐MA when grafting ratio reached at 5.6%, and the amount and diameter of particles increased with increasing of grafting ratio. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4425–4429, 2006     

Molecular weights of styrene–maleic anhydride copolymers

A dual-calibration method for the determination of molecular weights and molecular weight distribution of styrene–maleic anhydride copolymers (S/MA) by gel permeation chromatography (GPC) is introduced. It might be applicable to copolymers of other type. A linear relationship of intrinsic viscosity [η] and weight-average molecular weight (M?_w) for unfractionated S/MA in tetrahydrofuran (THF) at 25°C can be expressed by the equation The maleic anhydride content of the copolymers ranges from 5 to 50 mole-%, and the M?_w range is from 2 × 10⁴ to 7 × 10⁶. The plot of log [η] M?_w versus GPC elution volume of the S/MA copolymers falls on the same curve as that of the polystyrene standards in THF.     

Synthesis and characterization of solid‐phase graft copolymer of polypropylene with styrene and maleic anhydride

Polypropylene (PP) was modified by solid‐phase graft copolymerization with maleic anhydride (MAH) and styrene (St), using benzoyl peroxide as the initiator and xylene as the interfacial agent. Effects of various factors such as monomer concentration, monomer ratio, initiator concentration on grafting percentage, and acid value were investigated. The graft copolymer was characterized by Fourier transform infrared, pyrolysis gas chromatography—mass spectroscopy, and dynamic mechanical analysis, and the intrinsic viscosity of the extractive from the reaction product was investigated. The results showed that the grafting percentage and acid value of the graft copolymer of PP with two monomers (MAH and St) were considerably higher than those of the graft copolymer of PP with MAH alone. The graft segments were shown to be the copolymer of St and MAH with a substantial molecular weight. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 2482–2487, 2000     

Melt functionalization of EVA copolymers with maleic anhydride

Ethylene vinyl acetate (EVA) copolymers with different amounts of vinyl acetate were melt‐functionalized with maleic anhydride. The effect of benzoyl peroxide, t‐butyl perbenzoate, and dicumyl peroxide (DCP) as free‐radical initiators on the functionalization performance was studied. The crosslinking reactions occur to a larger extent than in polyethylene, indicating that the vinyl acetate groups favor the formation of free radicals. From all the experiments performed in this study, the recommended initiation system to achieve the best values of the functionalization degree and the lower gel content involves the use of DCP in a concentration of about 0.3 wt % and a maleic anhydride concentration around 5.0 wt %. From FTIR and TGA analyses, it is suggested that the hydrogen abstraction in the EVA copolymers occurs both in the methyl group of the acetate moiety and in the tertiary C—H. The free radicals generated in the tertiary C—H react with maleic anhydride in a higher proportion. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1799–1806, 1999     

Direct polymer reaction of poly(styrene‐co‐maleic anhydride): Polymeric imidization

Using direct polymer reaction of poly(styrene‐co‐maleic anhydride) (SMA), a synthesis of copolymer of styrene and N‐aryl succinimide (SMI) has been investigated. SMI copolymers were synthesized from SMA copolymers by a concerted two‐step reaction, which consisted of the condensation reaction (step 1) of SMA with aromatic amine to prepare a precursor, succinamic acid, for imide formation and the cyclodehydration reaction (step 2) of succinamic acid. In this article, the application of Searle's preparation method of N‐aryl or N‐alkyl maleimide to the direct polymer reaction for SMI was attempted. Compared with synthesis of monomeric imides, the imide formation in polymeric condition appeared to be a little more sensitive to the reaction condition. The optimum condition for maximum conversion was examined in terms of time, temperature, and the amount of reactants. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1187–1196, 1999     

Polymer supports based on maleic anhydride copolymers: Preparation of beaded copolymers of maleic anhydride on dimethylacrylamide prepolymers

A new technique is described whereby maleic anhydride copolymers are formed within the swellable beads of dimethylacrylamide pre-polymers. Incorporation of a divinyl compound during the copolymerization, or diamine condensation of a pre-formed soluble copolymer, provides a wide range of anhydride containing resins whose conversion to the corresponding acidic or succinimido derivatives, is briefly described.