• Macromolecular Research
• /
• v.17 no.5
• /
• pp.296-300
• /
• 2009

Ethylene-1-butene copolymers were prepared with $SiO_2$-supported $TiCl_4$ catalyst by changing of 1-butene/ethylene molar ratio in feed, and the resulting copolymers were analyzed using temperature rising elution fractionation (TREF) and crystallization fractionation (Crystaf) methods to investigated the influence of $C_4/C_2$ molar ratio in feed on chemical compositional distribution and other parameters such as molecular weight and its distribution. TREF analysis showed that the copolymers had a broad and bimodal chemical compositional distribution (CCD) regardless of the content of 1-butene in the copolymer. The chemical composition was in the range of 5 to 55 branches per 1,000 carbons for all copolymers prepared in the study. Furthermore, the broader CCD was revealed for the copolymers having the higher content of 1-butene. Crystaf analysis did not showed a bimodal CCD for the copolymers having the 1-butene content of less than 5.1 wt%. The lower crytalline part having 1-butene content in Crystaf analysis was less than of TREF analysis.

• Elastomers and Composites
• /
• v.36 no.1
• /
• pp.14-21
• /
• 2001

To increase the properties of EVA foam such as tensile strength, rebound resilience, and compression set, ethylene-1-butene copolymer (EtBC) was blended with EVA. After that crosslink characteristics of the blends and cell structures and mechanical properties of the foam were studied. As the amount of EtBC increased in EVA/EtBC blends, torque values of oscillating disc rheometer(ODR) increased and the foaming ratio decreased because the viscosity and crosslink density of EVA/EtBC blends increased. Foaming ratio and cell size of the foam increased by increasing the amount of foaming agent. When compared the mechanical properties of the foam which have same densities, tensile strength, rebound resilience, and compression set properties of the foam were improved by increasing the amount of EtBC in the EVA/EtBC blends.

• Journal of the Korean Chemical Society
• /
• v.31 no.1
• /
• pp.110-117
• /
• 1987

For the preparation of linear low density polyethylene (LLDPE), the copolymerization of ethylene and 1-butene was carried out with various catalysts of titanium alkoxidealkylaluminum compound in slurry phase. The effects of catalyst components, aging time, concentration of catalyst components, polymerization time and temperature on the catalytic activity and copolymer composition were examined. The properties of copolymer obtained were also considered with the correlation to the 1-butene contents. It has been found that the titanium tetra-n-butoxide-diethylaluminum chloride catalyst system was the most suitable for the production of LLDPE with higher catalytic activity, more 1-butene content and less soluble parts. The density, glass transition temperature, melting point and heat of fusion of copolymer were decreased with increasing 1-butene contents.

• Applied Chemistry for Engineering
• /
• v.9 no.3
• /
• pp.424-429
• /
• 1998

Cloud-point data at $230^{\circ}C$ and 1,800 bar are presented for two poly(ethylene-co-vinyl alcohol)(PEVA) copolymers[9.9mol% and 17.8mol% vinyl alcohol(VA)] in ethylene, propane, propylene, n-butane, 1-butene, dimethyl ether(DME), and chlorodifluromethane(CDFM). The static type experimental apparatus with a view cell has been used for the experiment at the high pressure and temperature. The pressure-temperature (P-T) loops of PEVA(9.9mol% VA) copolymer-DME mixtures are presented at copolymer concentrations of 1.4wt% to 20.0wt%. Also, we presented the phase behavior of PEVA(17.8mol% VA) copolymer-DME system at copolymer concentration of 1.9wt% to 6.8wt%. The cloud-point curves for the PEVA copolymers in dimethyl ether showed single phase above 480 bar as a result of the hydrogen bonding between the vinyl alcohol unit and dimethyl ether. The pressure-concentration(P-x) isotherm loops of PEVA(9.9mol% and 17.8mol% VA)-DME system are obtained. The cloud-point curves for PEVA(9.9mol% and 17.8 mol% VA) copolymers andthe ethylene, propane, propylene, n-butane, 1-butene, and CDFM all show negative slopes of phase behavior and are located at pressures below 1,800 bar. For PEVA copolymer-DME system(9.9mol% VA), cloud-point curves show positive slopes that decrease in pressures with decrease in temperature in the temperature range of $80^{\circ}C$ to $160^{\circ}C$.

• Polymer(Korea)
• /
• v.28 no.2
• /
• pp.162-169
• /
• 2004

Poly[styrene-b-(ethylene-1-butene)-b-styrene] triblock copolymer (SEBS) was functionalized with 0 to 3.0 phr maleic anhydride and the amount of dicumyl peroxide used as an initiator was varied from 0 to 0.3phr. The gel content of the modified SEBS was determined by xylene extraction and poly(oxymethylene) was blended with the modified SEBS. The impact, tensile, flexural strength and morphologies of the blends were investigated. The Izod impact strength of poly(oxymethylene) was improved through its blending with modified SEBS. However, the Izod impact strength of poly(oxymethylene)/modified SEBS blend decreased above 5% modified SEBS content. Regarding the effect of dicumyl peroxide content on the Izod impact strength, the blend had a maximum Izod impact strength when poly(oxymethylene) was blended with modified SEBS prepared with 0.1 phr dicumyl peroxide. It was also confirmed by SEM micrographs that the average particle size of modified SEBS in poly(oxymethylene)/modified SEBS blends was smaller than that of SEBS in poly(oxymethylene)/SEBS blends.

• Korean Chemical Engineering Research
• /
• v.45 no.4
• /
• pp.410-413
• /
• 2007

The effect of internal donor(ID) in the heterogeneous Ziegler-Natta catalyst on the ethylene-1-butene copolymerization and the molecular structure of the resulting copolymer was investigated. $SiO_2$-supported $TiCl_4$ catalysts having ID/Ti molar ratio of 0.5 were prepared with ethyaluminium dichloride, magnesium alkyl, 2-ethyl-1-hexanol and $TiCl_4$. Three different IDs were employed such as ethylbenzoate(EB), diisobuylphthalate(DIBP) and dioctylphthalate(DOP). ID-added catalyst showed a larger fraction of Ti(+3) compared to that of no ID-added catalyst. The EB-added catalyst showed the highest activity in copolymerization. Xylene soluble value decreased by more than 50 % with ID-added catalysts compared to that of no ID-added catalyst. Crystaf analysis showed the chemical compositional distribution of PE copolymer was improved in the case of DIBP-added catalyst significantly. It could be explained that the presence of ID could make more even active sites and block the non-stereospecific active sites.