Styrene-maleic Anhydride Copolymer Research Articles

Short Glass Fiber Reinforced PA 6 and ABS Blends

Abstract A 70:30 blend of polyamide 6 (PA 6) and acrylonitrile butadiene styrene terpolymer (ABS), with and without a compatibilizer, was used as the matrix for reinforcement with short glass fibers. The compatibilizer used was a copolymer of styrene maleic anhydride (SMA) and its level was kept at 5 wt.-% in the blend. The glass fiber content was varied from 10 to 30 wt.-%. The blends and corresponding composites were compounded using a single screw extruder and test samples were prepared by injection molding. Tensile, flexural and impact properties were determined using the injection molded test samples according to ASTM standards. Morphological studies were carried out on fractured tensile test specimens using scanning electron microscopy (SEM). In general, the mechanical properties improved by the addition of glass fibers to the blend matrices and increased with increasing glass fiber content. The compatibilizer (SMA) has no favorable effect on the mechanical properties of the composites although it has a significant effect on the blends of PA 6 and ABS. SMA increases the melt viscosity of the blend and its addition to the blend results in greater damage to the fibers in the composite during processing. The fiber-matrix adhesion appears to be better in the absence of SMA. The morphological observations have been correlated with mechanical properties.

Miscibility in terpolymer-copolymer blends

The phase behaviour of 50 50 blends of a series of terpolymers from styrene, maleic anhydride and acrylonitrile with styrene-acrylonitrile copolymers and styrene-maleic anhydride copolymers has been determined using the single glass transition temperature criterion. The appropriate expression for the overall blend interaction energy density according to the extended Flory-Huggins theory is examined and the general shapes of miscibility contours in composition space are deduced and presented in a novel manner. The experimental miscibility is dependent on both terpolymer and copolymer composition, and is well described by this expression using values of segmental interaction parameters available from the literature.

Model experiments for the interfacial reaction between polymers during reactive polymer blending

AbstractBilayer film Fourier transform infrared (FTIR) model experiments are designed to provide a well‐defined interface for study which can be probed by infrared spectroscopy during the interdiffusion and reaction of two reactive polymers. This provides a model experiment to determine the kinetics and extent of reaction between functionalized polymers during reactive polymer blending. This type of experiment provides data on the reaction at a stagnant interface which is necessary for the analysis of the interface while it is simultaneously undergoing deformation. It is also useful as a screening or preliminary experiment on reactive blending systems in that the extent of reaction may be followed for different systems at different temperatures. Experiments reported here trace the reaction of a styrene–maleic anhydride copolymer with two different amine terminated polymers. Results are obtained for the interdiffusion and reaction of a styrene‐maleic anhydride copolymer with two amine terminated polymers: a butadiene‐acrylonitrile copolymer and Nylon 11. The kinetics from these experiments include contributions due to both interdiffusion and chemical reaction. The chemical reaction kinetics may be isolated from the diffusion kinetics by performing experiments on well‐mixed systems which are prepared by casting films of the polymer mixtures from a mutual solvent. © 1994 John Wiley & Sons, Inc.

Rheology and morphology of starch/synthetic polymer blends

Corn starch and maleic anhydride functionalized synthetic polymers were melt blended in a Haake twin-screw extruder. The amount of starch in the blends was 60 and 70% by weight. The synthetic polymer used was either styrene maleic anhydride (SMA) or ethylene propylene maleic anhydride copolymer (EPMA). The blends did not exhibit normal thermoplastic behavior; and hence, rheological data was obtained by extrusion feeding the material through a slit die or cylindrical tube viscometer. The starch/SMA blends were extruded through a slit viscometer with a 45% half entry angle, while the starch/EPMA blends were extruded through a cylindrical tube viscometer with a half entry angle of 37.5°. For the blends, data could be obtained at low to moderate shear rates (10< γapp<200s−1). At higher shear rates, blends exhibited slip and/or degradation of starch. The viscosity of the blends exhibited shear-thinning properties. Regrinding and re-extruding through the viscometer a second time showed a significant reduction in shear viscosity for starch/SMA blends. Gel permeation chromatography data indicated that starch macromolecules degraded upon successive extrusion. Extensional viscosity, as estimated from entrance pressure drop method for starch/EPMA blends showed stretch thinning properties. Regrinding and re-extruding showed that the samples were more sensitive to changes in extensional viscosity as observed from the Trouton ratio versus extension rate plot. Optical microscopy showed the presence of starch granules after melt blending, the size of which was related to the torque (or stress) generated during extrusion. The higher the torque, the smaller the size of the starch granules. Successive extrusion runs reduced the number of unmelted granules.

The preparation and morphology of PPO–epoxy blends

AbstractPoly(phenylene oxide) (PPO) was found to be miscible in diglycidyl ether of bisphenol A (DGEBA) based epoxy. The PPO–DGEBA system exhibited upper critical solution temperature (UCST) behavior. The cloud point temperatures were measured and found to be sensitive to the mol wt of the epoxy resin. A series of PPO‐modified epoxies were cured with piperidine at 160°C, which is above the cloud point temperature. Upon cure, two phase solids were formed, which contained discrete PPO particles. However, the two‐phase particulate morphology was not uniform and numerous large, occluded PPO particles were observed. In order to improve the uniformity, several styrene‐maleic anhydride copolymers were evaluated as potential surfactants for PPO‐DGEBA bends. The formation of a uniform, particulate morphology was facilitated by the addition of a styrene–maleic anhydride copolymer, containing a 10:1 ratio of styrene to maleic anhydride. To our knowledge, this is the first time that an emulsifying agent has been added to improve the morphology of thermoplastic modified epoxies. © 1993 John Wiley &amp; Sons, Inc.

Reactive coupling of core-shell impact modifiers to polyamide matrices using styrene-maleic anhydride copolymers

Core-shell impact modifiers have the advantage of a predetermined particle size; however, they must be appropriately dispersed in and coupled to the matrix polymer in order to be effective for toughening engineering plastics which are notch-sensitive. These functions can result from physical interaction of the shell material with the matrix or by chemical reaction. For the latter the most obvious route is to combine reactive moieties into the shell chains during fabrication by emulsion polymerization that subsequently react with the matrix during melt processing. An alternative is considered here for dispersing and coupling modifiers with shells based on poly(methyl methacrylate), PMMA, in a polyamide matrix. Certain styrene-maleic anhydride copolymers, SMA, are miscible with PMMA, yet through the maleic anhydride moiety these copolymers can react with polyamides during melt processing (via amine end groups). This concept leads to very tough blends based on nylon 6 but not to those based on nylon 6,6. Evidence for the proposed role of the SMA copolymer was demonstrated by transmission electron microscopy. Properties and morphology were examined for two different SMA copolymers, two core-shell impact modifiers (butadiene-based and acrylic-based rubber cores), various mixing protocols and component proportions. An attempt is made to explain the responses observed.

Monoesterification of styrene–maleic anhydride copolymers with alcohols in ethyl benzene: Catalysis and kinetics

AbstractA kinetic investigation on the monoesterification reaction of the maleic anhydride residue (MA) in styrene‐maleic anhydride copolymers with aliphatic alcohols was carried out in ethyl benzene solution. By comparison to classic catalysts such as tributylamine (TBA) and pyridine, 4‐dimethylaminopyridine (4DMAP) is by far the most effective catalyst for this reaction. While both general base and nucleophilic mechanisms contribute to the reaction catalyzed by TBA or pyridine, a nucleophilic mechanism prevails with 4DMAP. This reaction is reversible, and its chemical equilibrium constant decreases significantly with increasing temperature. Both kinetic and thermodynamic results showed that in the presence of 4DMAP, the forward and reverse reactions are second and first order, respectively. The existence of side reactions, reactivity of two styrene‐maleic anhydride copolymers of different MA contents as well as two aliphatic alcohols of different lengths are also addressed. © 1993 John Wiley &amp; Sons, Inc.

The activation of human plasma prekallikrein as a hemocompatibility test for biomaterials. II. Contact activation by EVAL and EVAL-SMA copolymers.

The activation of human plasma prekallikrein (PKK) to kallikrein (KK), induced by the contact of blood with foreign materials, is a useful in vitro hemocompatibility test. Kallikrein is easily detected by its reaction with the chromogenic substrate H-D-Pro-Phe-Arg-pNA, which releases p-nitroaniline, revealed by its absorption at 405 nm. This test, which was already carried out by evaluating PKK activation by the 'end-point' method, has been carried out in this work by the more accurate 'initial velocity' method, i.e. by evaluating the activation from the initial rates of the KK-substrate reaction. The tests were carried out on the following materials: borosilicate glass (as a high-activation reference material), silicone (as a low-activation reference material), the commercial biomaterial Cardiothane 51, three graft copolymers synthesized in our laboratory by reacting ethylene-vinyl alcohol copolymer (EVAL) with styrene-maleic anhydride copolymer (SMA), and EVAL itself. A mathematical treatment based on a simple kinetic model has been used for a first-approximation evaluation of the PKK-activating power of the materials tested. The quite low activating power of the EVAL-SMA copolymers, which are easily processable into water-permeable hollow fibers, suggests the possibility of their use in blood dialyzers.

Impedance spectroscopy and cyclic voltammetry at bare and polymer coated glassy carbon electrodes

Abstract Influence of electrochemical pretreatment of a glassy carbon electrode on electrochemical parameters of the charge transfer is investigated. The couple ferro/ferricyanide serves as a model system. Parameters are calculated from data obtained from impedance spectroscopy and cyclic voltammetry measurements supposing a pure quasireversible case. By electrochemical pretreatment the heterogeneous charge transfer constant is enhanced from the range of 0.0001 up to higher than 0.01 cm s −1 . The diffusion coefficient has been evaluated to be about 8 × 10 −6 cm 2 s −1 . When the electrode is coated by styrene—maleic anhydride copolymer, the polymer swells in aqueous medium until signals similar to bare electrodes are obtained. They can be attributed to the pinhole diffusion of the electrode substrate. It can be shown that parameters, determined from impedance measurements, fit experimental data very well.

Toughening styrene maleic anhydride copolymers with functionalized ethylene propylene rubbers

This study describes the impact modification of brittle styrene maleic anhydride (SMA) copolymers with primary amine functionalized ethylene propylene (EP) elastomers. Compatibilization of functional EP in SMA is achieved by chemical reaction of complementary functional groups to form a graft in situ. FTi.r. methods and differential solvent extraction techniques demonstrate graft copolymer formation. Morphological studies indicate that the domain size of the dispersed elastomer ranges from 1 to 3 μm. This may represent an optimum for SMA, which fails by crazing. Rheological characteristics of SMA and SMA/EP blends were studied by using both capillary and parallel-plate viscometers. Graft polymer formation does not substantially increase viscosity at high strain rate, but introduces an apparent yield stress at low shear.

Amidification of poly(styrene-co-maleic anhydride) with amines in tetrahydrofuran solution: A kinetic study

The kinetics of the reaction between a styrene-maleic anhydride copolymer (SMA) and amines was investigated in tetrahydrofuran solution between 0°C and 40°C. This reaction converts the maleic anhydride (MA) into the corresponding amide-acid, while the consecutive reaction of the generated acid with amine forming a diamide or transformation of the acid-amide into the imide was not observed. The amine reactivity follows the order: 1-octylamine> >1-methyl hexylamine> >1,1-dimethyl propylamine or dibutylamine, demonstrating that the amine reactivity depends, to a large extent, upon its steric hindrance. This reaction is reversible as shown by IR at high temperatures, but the reverse reaction was undetectable between 0 and 40°C. The overall reaction involves spontaneous and autocatalytic reactions, and the overall reaction rate can be written as:-d[MA]/dt=k0[MA][-NH2]+k1[MA][-NH0]2. In the case of 1-octylamine below 0.02 M, the spontaneous reaction dominates (i.e, k0> >k1[-NH2]).

In situ compatibilization of polystyrene/polyethylene blends using amino‐methacrylate‐grafted polyethylene

AbstractBlends of a styrene–maleic anhydride copolymer (SMA) with polyethlene (PE) or polyethylene melt grafted with tertiary (PE‐g‐DMAEMA) or secondary (PE‐g‐tBAEMA) amino methacrylate were prepared by blending in a batch melt mixer. The morphology of these blends at various compositions was examined with a scanning electron microscope (SEM) and related to their tensile and impact properties. The SMA/PE blends are found to have the typical coarse morphology of incompatible blends and poor mechanical properties, while their reactive conterparts, SMA/PE‐g‐DMAEMA or SMA/PE‐g‐tBAEMA blends, show finer morphology and modestly improved tensile and impact strength. This was attributed to chemical interaction of the acidic anhydride and the basic amino groups. The greater improvement in morphology for SMA/PE‐g‐tBAEMA than for SMA/PE‐g‐DMAEMA suggests a stronger interaction between the secondary amino groups and the anhydride groups, possibly with the formation of SMA‐g‐tBAEMA‐g‐PE graft polymer through amide covalent bonds. The amide formation appears to occur at the interfacial region in the blends and is too little to be detected by Fourier transform infrared (FTIR) spectra. However, differential scanning calorimeters (DSC) and the viscosity measurements indicate crystallinity and molecular weight changes for the SMA/PE‐g‐tBAEMA blends, supporting an argument for the formation of SMA‐g‐tBAEMA‐g‐PE grafts at the phase interface.

Neutron reflectivity studies of spread monolayers of derivatives of styrene-maleic anhydride copolymers at the air-water interface

Neutron reflectivity studies of spread monolayers of derivatives of styrene-maleic anhydride copolymers at the air-water interface

Quantitative determination of the content of cis/trans configurations of maleic anhydride units in p-methoxystyrene-maleic anhydride copolymers by 13C NMR DEPT experiments

The configuration of maleic anhydride units in p-methoxystyrene-maleic anhydride copolymers prepared in methyl ethyl ketone at 50°C was studied using 13C NMR DEPT experiments. The ratio of cis (erythro) to trans (threo) configurations was found to increase with the tendency of the monomer units to alternate, remaining almost constant at approximately 1.33 when the mole fraction of maleic anhydride in the feed was larger than 0.30 and the monomer unit sequence was almost completely alternating. Also, para substitution on the styrene monomer units was found to greatly improve the resolution of the 13C NMR DEPT spectra for copolymers of p-methoxystyrene and p-chlorostyrene with maleic anhydride as compared with that of styrene-maleic anhydride copolymers.

Blends of styrene/maleic anhydride copolymers with polymethacrylates

AbstractThe phase behavior of a series of styrene/maleic anhydride (SMA) copolymers with various polyacrylate and polymethacrylate homopolymers has been investigated using various techniques. None of the polyacrylates are miscible with SMA copolymers. Poly (methyl methacrylate) (PMMA) poly(ethyl methacrylate) (PEMA) and poly(n‐propyl methacrylate) (PnPMA), are miscible with these copolymers over a certain range of maleic anhydride contents; whereas, the higher methacrylates apparently have no region of miscibility. For PEMA and PnPMA, the miscibility windows extend through 0% MA; hence, polystyrene is miscible with these polymethacrylates although the lower critical solution temperature is quite low. The exothermic heat of mixing styrene and ester analogs found here supports the observed miscibility of polystyrene with ethyl, n‐propyl, and cyclohexyl (reported elsewhere) methacrylates. Lattice fluid interaction parameters for styrene‐methacrylate obtained from the cloud points of these blends agree quite well with the Flory—Huggins parameters obtained from copolymer miscibility windows.

Single-ion conductivity in comblike polymers

We have prepared comblike polymers based on styrene-maleic anhydride and ethylene-maleic anhydride copolymer backbones. Reactions have been carried out in which the cyclic anhydrides were ring opened with the concomitant formation of ester groups on one of the carbonyl functions. The remaining carbonyl group is part of a carboxylic acid. The alcohol moieties are either the monomethyl ethers of triethylene glycol or of polyethylene glycol (MW 350). The resulting polymers were then converted to their lithium salts. Complex impedance plane measurements of the ionic conductivity in these lithiated polymers have been performed. Cole–Cole plots indicate that there is no electronic contribution to the overall conductivity. The ionic conductivity in the case of the triethylene glycol comb polymer is about 10−9 S cm−1, whereas that of the polymer with the longer ethylene oxide chain is 10−7 S cm−1 at room temperature. From the chemical nature of these polymers, it is presumed that all the conductivity is due to the mobility of the Li ion. These data will be compared to the results other laboratories have had with different single-ion conducting polymers.

Radioimmunological determination of total thyroxin by antibodies immobilized on polystyrene tubes coated with styrene-maleic anhydride copolymers

In this new technique for preparing activated polystyrene tubes for assay of human thyroxin (T4) we coated plastic with styrene-maleic anhydride copolymers. The quantity of antibodies immobilized on these tubes was considerably greater than on non-activated polystyrene tubes, and the time required for immobilization was shortened. Calibration curves were plotted, and determination of total T4 in 200 serum samples confirmed the expected increase in sensitivity as compared with a commercial (Gammacoat) method. The manufacturing procedure is simple and could easily be automated. Thus, such copolymer-coated tubes constitute an advantageous and reliable component in the assay of total T4 that can be used to improve the sensitivity of this and various other radioimmunological determinations.

Synthesis and microstructure of organotin polymers

IR spectroscopy and derivatography have been used to analyze the intramolecular conversions of the bis-tri- n-butylstanny esters of maleic and fumaric acids and also their copolymers. Thermal isomerization of the maleates to fumarates does not occur up to temperatures of the onset of decomposition of the substances. On free-radical copolymerization of the maleates with styrene there is partial isomerezation and in the structure of the chain, units of the diesters of maleic (85–90%) and fumaric (10–15) acids are found. In the alternating styrene-maleic anhydride copolymers after esterification by organotin oxides the number of isotactic diads may be 10%. Change in the microtacticity is explained by the formation of polycarbanions. Heating of the copolymers to 500 K leads to exothermal change in the configuration of the maleate units and then to their cyclization with the formation of maleic anhydride units.

Studies on alternating radical copolymerization: analysis of microstructures of styrene-maleic anhydride, styrene-acrylonitrile, and styrene-methyl methacrylate copolymers by fluorescence spectroscopy

Etude des copolymeres en variant le rapport molaire des 2 monomeres; augmentation de la proportion des diodes styrene-styrene dans le copolymere S/MA avec la proportion du styrene dans le melange reactionnel. Le copolymere S/A obtenu par copolymerisation amorcee par ZnCl 2 est reellement alterne alors que le copolymere S/MMA prepare dans les memes conditions est sensiblement different

Evaluation of compositional distributions of styrene-maleic anhydride copolymers by thin-layer chromatography/pyrolysis-gas chromatography

A method for the evaluation of the compositional distributions in styrene (St)-maleic anhydride (MAN) copolymers by thin-layer chromatography/pyrolysis-gas chromatography is described. A St-MAN copolymer sample (average St content = 75 mole %) was used after methyl esterification by diazomethane. The fractionated samples of the original copolymer were pyrolyzed at 590°C using a Curie-point pyrolyzer and the resulting products were separated by gas chromatography. The resulting pyrograms were interpreted in terms of the compositional distributions of the copolymer. The St content in the samples could be determined using the linear relationship between the St content in the samples and [St]/([St] +[MA]) ratio (where MA = methyl acrylate) in the pyrolytic products. The fractionated samples having higher R F values proved to have a higher St content.