Preparation and characterization of ethylene-propylene copolymer grafted with acrylamido tertiary butyl sulfonic acid

Grafting of acrylamido tertiary butyl sulfonic acid (ATBS) onto ethylene-polypropylene copolymer (EPM) was carried out by using a reactive processing method. The grafting copolymer was characterized by means of WAXD, FT-IR, ESCA, and DSC. Improved thermal stability was observed for graft copolymer. Effects of the monomer and the initiator concentrations, reactive temperature, and time on grafting degree were investigated. (C) 1997 John Wiley & Sons, Inc.

Toughened poly(butylene terephthalate) by epoxided ethylene-propylene-diene-rubber

Blends of poly (butylene terephthalate) (PBT) and epoxided ethylene-propylene-diene terpolymer (EEPDM) were prepared. Their mechanical properties and morphology were studied by Izod impact test machine and scanning electronic microscope respectively, It was found that the notched Izod impact strength of blend PBT/EEPDM was as about 23 times as that of pure PET and about 10 times as that of blend PBT/EPDM at room temperature, The dispersed rubber particles were much smaller and the phase boundary was more blurred in blend PBT/EEPDM than in blend PBT/EPDM. The toughness of blend PBT/EEPDM was much more better than that of blend PET and PBT/EPDM, which was in good agreement with the difference between their morphologies.

Crystalline behavior and critical crystalline sequence length of propylene/alpha-olefin copolymer

The melting points(T-m), crystalline temperature(T-c) and crystallinity(chi(c)) of propylene/alpha-olefin (pentene-l, octene-1 and decene-1) copolymers have been investigated, The results show that the T-m, T-c and chi(c) of the copolymers are lower than those of propylene homopolymer, indicating that lower alpha-olefin incorporation in copolymer has strongly hampered the crystallization of propylene, From critical crystalline sequence length of several propylene/alpha-olefin copolymers, it can be seen that a long chain alpha-olefin has much stronger effect on crystallization of PP than a short alpha-olefin does.

Thermal analysis of ethylene-propylene copolymer-grafted-glycidyl methacrylate

The thermal properties of ethylene-propylene copolymer grafted with glycidyl methacrylate (EP-g-GMA) were investigated by using differential scanning calorimetry (DSC). Compared to the plain ethylene-propylene copolymer (EP), peak values of melting temperature (T-m) of the propylene sequences in the grafted EP changed a little, crystallization temperature (T-c) increased about 8-12 degrees C, and melting enthalpy (Delta H-m) increased about 4-6 J/g. The isothermal and nonisothermal crystallization kinetics of grafted and ungrafted samples was carried out by DSC. Within the scope of the researched crystallization temperature, the Avrami exponent (n) of ungrafted sample is 1.6-1.8, and those of grafted samples are all above 2. The crystallization rates of propylene sequence in EP-g-GMA were faster than that in the plain EP and increased with increasing of grafted monomer content. It might be attributed to the results of rapid nucleation rate. (C) 1996 John Wiley & Sons, Inc.

The determination of ethylene-propylene copolymer-grafted-glycidyl methacrylate by the contact angle method

The contact angles theta of some liquids on ethylene-propylene copolymer-grafted-glycidyl methacrylate (EPM-g-GMA) were measured. The critical surface tensions r(c) of EPM-g-GMA were evaluated by the Zisman Plot (cos theta versus r(L)), Young-Dupre-Good-Girifalco plot (1 + cos theta versus 1/r(L)(0.5)) and log (1 + cos theta) versus log(r(L)) plot. The following results were obtained: the r(c) values varied significantly with the estimation methods. The critical surface tension r(c) decreased with the increase of the degree of grafting of EPM-g-GMA.

Properties of ethylene-propylene copolymer/PA-1010 blends using ethylene-propylene copolymer-graft-acrylic acid as a compatibilizing agent

The modification of ethylene-propylene copolymer (EP) has been accomplished by radical EP-graft-acrylic acid (EP-g-AA) has been used to obtain ternary PA/EP/EP-g-AA blends by melt mixing. Different blend morphologies were observed by scanning electron microscopy; the domain size of the EP-dispersed phase in the polyamide 1010 matrix of compatibilized blends decreased compared with that of uncompatibilized blends. It is found that EP-g-AA used as the third component has a profound effect on the mechanical properties of the resulting blends. This behavior has been attributed to serious chemical interactions taking place between the two components. Thermal analysis shows that some thermal properties of PA in compatibilized PA/EP/EP-g-AA changed because of chemical reactions taken place during the blending process. Wide angle x-ray diffraction measurements also confirmed this result. (C) 1996 John Wiley & Sons, Inc.

Crafting of glycidyl methacrylate onto ethylene-propylene copolymer: Preparation and characterization

Ethylene-propylene copolymer (EP) was functionalized with glycidyl methacrylate (GMA) by means of a radical-initiated melt grafting reaction. FTIR and ESCA were used to characterize the formation of EP-g-GMA copolymers. The content of GMA in EP-g-GMA was determined by using hydrochloric acid/xylene titration. Effects of concentrations of GMA and dicumyl peroxide on grafting rate were studied. It was found that contact angles of the water on surfaces of EP-g-GMA samples increased with increasing content of GMA in EP-g-GMA. The influence of the content of GMA on the crystallization structure of EP-g-GMA was investigated by DSC and WAXD. Compared with the plain EP, the crystallization temperature of propylene blocks of EP-g-GMA increased over 10 K, and the melting temperature and crystallinity decreased somewhat. Functionalization of EP led to the change of the crystal form of propylene blocks from the mixed form of alpha and beta into the alpha form. (C) 1996 John Wiley & Sons, Inc.

STEREOCHEMICAL CONTROL IN PROPYLENE POLYMERIZATION WITH A ASYMMETRICALLY SUBSTITUTED TITANOCENE/METHYLALUMINOXANE CATALYST

A new mono-substituted titanocene, (eta(5)-cyclopentadienyl) [eta(5)-(1-(4-methoxyphenyl) cyclohexyl) cyclopentadienyl] dichlorotitanium (I), has been prepared via a novel modified synthesis, and its X-ray crystal structure has been determined. It crystallizes in the orthorhombic space group P2(1)2(1)2(1) with cell constants a=0.968 0(5) nm, b=1.284 6(5) nm, c=1.694 4(6) nm, Z=4, R=0.066. The I/methylaluminoxane (MAO) catalyst system produces at different polymerization temperatures either an isotactic or a syndiotactic polypropylene, both of which have the combined influence of enantiomorphic-site control and chain-end control, or an atactic polypropylene controlled by Bernoullian propagation mechanism.

EFFECT OF ETHYLENE-PROPYLENE COPOLYMER WITH RESIDUAL PE CRYSTALLINITY ON MECHANICAL-PROPERTIES AND MORPHOLOGY OF PP/HDPE BLENDS

Morphology and mechanical properties of polypropylene (PP)/high density polyethylene (HDPE) blends modified by ethylene-propylene copolymers (EPC) with residual PE crystallinity were investigated. The EPC showed different interfacial behavior in PP/HDPE blends of different compositions. A 25/75 blend of PP/HDPE (weight ratio) showed improved tensile strength and elongation at break at low EPC content (5 wt %). For the PP/HDPE = 50/50 blend, the presence of the EPC component tended to make the PP dispersed phase structure transform into a cocontinuous one, probably caused by improved viscosity matching of the two components. Both tensile strength and elongation at break were improved at EPC content of 5 wt %. For PP/HDPE 75/25 blends, the much smaller dispersed HDPE phase and significantly improved elongation at break resulted from compatibilization by EPC copolymers. (C) 1995 John Wiley & Sons, Inc.

COMPATIBILIZATION AND STRUCTURE OF POLY(PROPYLENE) NYLON-12 BLENDS

In this paper, scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD) were used to study the structure and compatibilization of poly(propylene) (PP)/nylon-12 (PA 12) blends. The compatibilizatio

STRUCTURE AND CATALYTIC ACTIVITY FOR PROPYLENE OXIDATION OF BI-MO-NB COMPLEX OXIDE CATALYSTS

The structure and catalytic,activity for propylene oxidation of series oxides B2Mo3-3X-Nb2XO12-4X (X=0.00, 0.02, 0.05, 0.10, 0.15, 0.20, 0.25) have been studied by means of XRD, IR, Raman, SEM, ESR and so on. The results showed that in the range of X < 0.

UNSTEADY DIFFUSION KINETICS OF ZIEGLER-NATTA HETEROGENEOUS CATALYST POLYMERIZATION .4. PREDICTION OF EXPERIMENTAL RESULTS OF PROPYLENE ETHYLENE 1-HEXADECENE TERPOLYMERIZATION

The prediction, based on unsteady diffusion kinetics, of the enhancement of reactivity and incorporation of 1-hexadecene in its copolymerization with propylene on adding a small amount of ethylene (increase from 5,2 mol-% to 10,8 mol-% when 2% of ethylene was added, and to 16,1 mol-% when 5% was added) was verified in the terpolymerization of propylene/1-hexadecene/ethylene on a commercial Solvay-type delta-TiCl3 catalyst. The catalyst efficiency was thus also increased. These augmentations originate from the increase in diffusion coefficient of 1-hexadecene at the catalyst surface when the PP crystallinity decreases on introduction of ethylene. Calculation based on unsteady diffusion kinetics showed that the order of diffusion coefficients ethylene > propylene > 1-hexadecene is reversed as the monomer concentration increases when the monomers are not at their equilibrium concentration. Sequence distribution as determined by means of C-13 NMR revealed a tendency of blocky structure rather than a Bernoullian one. The terpolymer compositions obtained by means of an IR method developed in this work conform rather well with the NMR results. Results in this work not only support the unsteady diffusion kinetics but also provide a new route to prepare olefinic copolymer rubbers with heterogeneous titanium catalysts.

MISCIBILITY AND PHASE-BEHAVIOR IN BLENDS OF POLY(HYDROXYETHER OF BISPHENOL-A) WITH POLY(ETHYLENE OXIDE-CO-PROPYLENE OXIDE)

The miscibility of poly(hydroxyether of bisphenol A) (phenoxy) with a series of poly(ethylene oxide-co-propylene oxide) (EPO) has been studied. It was found that the critical copolymer composition for achieving miscibility with phenoxy around 60-degrees-C is about 22 mol % ethylene oxide (EO). Some blends undergo phase separation at elevated temperatures, but there is no maximum in the miscibility window. The mean-field approach has been used to describe this homopolymer/copolymer system. From the miscibility maps and the melting-point depression of the crystallizable component in the blends, the binary interaction energy densities, B(ij), have been calculated for all three pairs. The miscibility of phenoxy with EPO is considered to be caused mainly by the intermolecular hydrogen-bonding interactions between the hydroxyl groups of phenoxy and the ether oxygens of the EO units in the copolymers, while the intramolecular repulsion between EO and propylene oxide units in the copolymers contributes relatively little to the miscibility.

RADIATION STABILITY OF PERFLUOROETHYLENE PROPYLENE COPOLYMER

The gel content of crosslinked perfluoroethylene-propylene copolymer was obtained by extraction with fluoro-chloro oil. It was then treated by the Charlesby-Pinner equation. The results obtained revealed that both the gelation dose and the ratio of fracture to crosslinking density decreased with increasing irradiation temperature.