The miscibility of homopolymer random copolymer blends .1. Poly(styrene-co-acrylonitrile) poly(ethyl methacrylate) and poly(styrene-co-acrylonitrile) poly(methyl methacrylate) blends

The miscibility of blends of poly(styrene-co-acrylonitrile) (SAN) with poly(methyl methacrylate) (PMMA) or poly(ethyl methacrylate) (PEMA) has been investigated by means of NMR and DSC techniques. It is found that there are intermolecular interactions between the phenyl groups in SAN and carbonyl groups in PMMA or PEMA, and the strength of this intermolecular interaction strongly depends on the properties of ester side groups in PEMA or PMMA, composition of the blends and a certain composition of the copolymer. It is this specific interaction instead of the intramolecular repulsion force within the copolymer that plays a key role for the miscibility of SAN/PMMA and SAN/PEMA blends.

Synthesis and characterization of aromatic liquid crystalline poly(ester-imide)s derived from an imidodicarboxylic acid

A new class of liquid crystalline poly(ester-imide)s was synthesized by melt polycondensation. The basic physical properties of the resulting polymers were investigated by differential scanning calorimetry (d.s.c.), wide-angle X-ray diffraction (WAXD), polarized light microscopy, scanning electron microscopy (SEM), thermogravimetric analysis (t.g.a.), and rheological and mechanical testing. All of these poly(ester-imide)s were amorphous, as reflected by the results obtained from the WAXD and d.s.c. studies. Characterization and comparison of these poly(ester-imide)s with the corresponding polyesters suggested that the introduction of imide groups into the polyester chain is favourable for the formation of liquid crystalline phases. These results, together with the rheological studies, suggested that there existed a form of strong inter- or intramolecular electron donor-acceptor interaction which played a significant role in the liquid crystalline properties of the poly(ester-imide)s. The polymer products thus obtained exhibited good mechanical properties, with flexural strengths and moduli as high as 174 MPa and 6.9 GPa, respectively. The morphology of the fracture surfaces of extruded rod samples showed a sheet-like structure which consisted of ribbons and fibres oriented along the flow direction. The glass transition temperatures and thermal stabilities of the polymers were improved by the incorporation of imide groups. Copyright (C) 1996 Elsevier Science Ltd.

Studies on polyepichlorohydrin-based polyurethane/poly(MMA-co-St) IPNs

Interpenetrating polymer networks of polyepichlorohydrin-based polyurethane/poly(MMA-co-St) have been prepared with simultaneous mettled by changing the weight fraction of MMA(W-MMA) in copolymer of MMA with styrene. The IPNs have been studied by DSC, TEM and dynamic mechanical spectroscopy(DMS). The results show that the IPNs have only one T-g, when W-MMA is greater than 0. 6. But when W-MMA IMA is less than 0. 4, the IPNs have two T(g)s, and phase separation is observed on TEM. The phenomenon is explained according to the solubility parameters(delta) and the fraction of hydrogen bond(delta(h)) of P (MMA-co-St). The study reveals that there is a close correlation among the delta, domain size and mechanical properties of PU (PECH)/P(MMA-co-St) IPN.

SYNTHESIS AND PROPERTIES OF POLY(ANILINE-CO-ANISIDINE)

Aniline and ortho-anisidine were chemically copolymerized at various temperatures and monomer compositions. Copolymers completely soluble in THF are prepared and characterized.

PROTONIC ACID-DOPING OF POLY-ORTHO-METHYLANILINE

Poly-o-methylaniline (poly-o-toluidine) was doped by some protonic acids. It was found that the acidity, molecular size and oxidizing ability of protonic acids affected the doping level and conductivity of polymer obtained to some extent. The organic acid

GLASS-TRANSITION AND CRYSTALLIZATION OF POLY(VINYL ALCOHOL)-G-POLY(METHYL METHACRYLATE) GRAFT-COPOLYMERS

The glass transition behaviour, microphase separation morphology and crystallization of poly(vinyl alcohol)-g-poly(methyl methacrylate) graft copolymers (PVA-g-PMMA) were studied. A lamellar microphase separation morphology was formed, even for a copolyme

胆甾液晶／聚合物多组分体系的结构与性能研究（Ⅲ）──ChN／poly（MMA－CO－BMA）混合体系的形态结构

应用Ｘ射线衍射、偏光显微镜及电子显微镜研究了胆甾液晶与甲基丙烯酸甲酯（ＭＭＡ）─甲基丙烯酸丁酯（ＢＭＡ）无规共聚物共混体系的形态结构。研究了体系的结晶态及液晶态的行为和共聚物含量及组成对光学织构的影响。

胆甾液晶／聚合物多组分体系的结构与性质研究Ⅳ．ChN／Poly（MMA－co－BMA）混合体系的X－射线衍射研究

用Ｘ－射线衍射法详细研究了ＣｈＮ／Ｐｏｌｙ（ＭＭＡ－ｃｏ－ＢＭＡ）共混体系在胆笛（Ｃｈ）相，近晶（Ｓ）相及结晶（Ｋ）态的分子排列。并给出了将液晶态的分子排列冻结在体系中，从而实现信息存储功能的条件。

WATER-SOLUBLE AND AMPHIPHILIC POLYMERS .11. GRAFT-POLYMERIZATION OF ACRYLIC-ACID ON POLY(VINYL ALCOHOL)

The graft polymerization of acrylic acid(AA) on poly(vinyl alcohol) (PVAL) has been investigated by using either potassium persulfate (KPS) or ceric ammonium nitrate(CAN) as an initiator. In the case of KPS initiation, the formation of the graft polymer always lags behind the homopolymer formation. The graft polymer is separated by acetone, and the increase of reaction temperature favors the homopolymer formation at the early stage. In the case of CAN initiation, graft polymers with a high PAA content can hardly be obtained when the polymerization is performed under nitrogen and at < 0.06 mol/L HNO3 concentration. It has been found that incorporation of a small amount of oxygen in a protective nitrogen gas accelerates markedly the graft polymerization, and that the resulting graft polymers can not be separated by acetone precipitation technique in most cases. The Dalian nitrogen(containing 0.7% oxygen) is a good protective gas for CAN-initiated PVAL-AA graft polymerization.

ISOPOLYMOLYBDIC ACID-POLY(4-VINYL)PYRIDINE FILM MODIFIED ELECTRODE

Electrochemical polymerization of 4-vinylpyridine produced a uniform poly(4-vinyl)pyridine(PVP) film on the glassy carbon (GC) electrode surface. The isopolymolybdic acid-PVP film-modified electrode was prepared by soaking the PVP/GC electrode in the 0.05 M H2SO4 aqueous solution containing 0.005 M isopolymolybdic acid (H4Mo8O26). The latter (catalyst) is incorporated and held in the PVP film electrostatically. The electrochemical behavior and electrocatalytic properties of this H4Mo8O26-PVP/GC electrode was described. The results indicate that this modified electrode has good stability and electrocatalytic activity on the reduction of chlorate and bromate ions in aqueous solution. The catalytic process is regarded as an EC mechanism.

CRYSTALLIZATION KINETICS OF MIXTURES OF POLY(EPSILON-CAPROLACTONE) AND POLY(STYRENE-CO-ACRYLONITRILE)

The crystallization kinetics in mixtures of poly(epsilon-caprolactone) (PCL) and poly(styrene-co-acrylonitrile) (SAN) has been investigated as the function of composition and crystallization temperature. The isothermal growth rates of PCL spherulites decrease with increasing concentration of SAN. Because of the miscibility of PCL/SAN mixtures, the radial growth rates of the spherulites are described by a kinetic equation including the interaction parameter and the free energy for the formation of crystal nuclei. The interaction parameter obtained from the fitting of the kinetic equation with experimental data is in good agreement with that obtained from melting point depression. Folding surface free energies decrease with the increase of SAN concentration. In light of these results, it is suggested that, for the PCL/SAN mixtures, the noncrystallizable SAN polymer reduces the mobility of crystallizable PCL polymer so that the growth rates decrease with the increase of noncrystallizable component fraction.

DYNAMIC SCALING AND FRACTAL BEHAVIOR OF SPINODAL PHASE-SEPARATION IN POLYMER MIXTURES OF POLY(METHYL METHACRYLATE) WITH POLY(STYRENE-CO-ACRYLONITRILE)

Dynamic scaling and fractal behaviour of spinodal phase separation is studied in a binary polymer mixture of poly(methyl methacrylate) (PMMA) and poly(styrene-co-acrylonitrile) (SAN). In the later stages of spinodal phase separation, a simple dynamic scaling law was found for the scattering function S(q,t):S(q,t) approximately q(m)-3S approximately (q/q(m)). The possibility of using fractal theory to describe the complex morphology of spinodal phase separation is discussed. In phase separation, morphology exhibits strong self-similarity. The two-dimensional image obtained by optical microscopy can be analysed within the framework of fractal concepts. The results give a fractal dimension of 1.64. This implies that the fractal structure may be the reason for the dynamic scaling behaviour of the structure function.

THE RING-BANDED SPHERULITE STRUCTURE OF POLY(EPSILON-CAPROLACTONE) IN ITS MISCIBLE MIXTURES WITH POLY(STYRENE-CO-ACRYLONITRILE)

The structure of the PCL spherulite in poly(epsilon-caprolactone)/poly(styrene-co-acrylonitrile) (PCL/SAN) blends was investigated by optical microscopy and small angle light scattering. The spherulite structure with a Maltese cross has been observed in pure PCL. Similar PCL/SAN blends exhibited not only spherulites with a Maltese cross, but also distinct extinction rings. The H(v) light scattering pattern especially caused diffraction rings in PCL/SAN blends but not in pure PCL. The spherical symmetry of spherulite PCL becomes more incomplete and the twist of the lamella becomes more irregular with increasing SAN content. It is found that the spherulite structure of PCL/SAN blends is dependent on the crystallization temperature and the concentration of SAN in PCL/SAN blends.

INVESTIGATION OF PHASE SEPARATION BEHAVIOR IN POLY (METHYL METHACRYLATE)/POLY (STYRENE-CO-ACRYLONITRILE) MIXTURES WITH PULSED NUCLEAR MAGNETIC RESONANCE

Thermally induced phase separation in the mixture of poly (methyl methacrylate) (PMMA) with poly(styrene-co-acrylonitite (SAN) has intern studied with pulsed nuclear magnetic resonance(NMR) in single spin-lattice retaxation time T-1 of the eornpatibl. mixture two T-1 corresponding to those of PM MA-rich and SAN-rich comairis. Meanwhile, both T-1 gradually changing with annealing time provides the direct evidence that the phase separation takes place with a decomposition mechanism. Diffusion coeffieient was to lac negative, indicating an uphal diffusion characteristics, The basic parameters governing its kinetics were estimated using NMR date which were in good agreement with those evaluated from time-resolved light scattering experiments for a 60/40(PMMA/SAN) mixture annealed at 180.0 degrees C.

MISCIBILITY OF POLY(EPICHLOROHYDRIN) WITH POLY(VINYL ACETATE) AND POLY(STYRENE-CO-ACRYLONITRILE)

The phase behaviours of poly(vinyl acetate) (PVAc) and poly(styrene-co-acrylonitrile)s (SAN) with poly(epichlorohydrin) (PECH) were examined using differential scanning calorimetry and an optical method using a hot plate. The PECH/PVAc blends showed LCST behaviour. The observed miscibility is thought to be a result of hydrogen-bonding interactions between the alpha-hydrogen atoms of PECH and the carbonyl groups of PVAc. Two SAN copolymers with an acrylonitrile (AN) content of 18 wt% (SAN18) and 25 wt% (SAN25), respectively, were also found to exhibit miscibility with PECH. No phase separation occurred by heating up to about 280-degrees-C, and the individual blend has a single, composition-dependent glass transition temperature. The formation of miscible PECH/SAN blends can be considered as a result of the intramolecular repulsion between styrene and AN units in SAN.