99/03690 Method for utilization of low-molecular-weight polyethylene, a waste from the manufacture of low-density polyethylene

The influence of molecular architecture on interfacial self-adhesion above polyethylene film melt temperature was examined in this study. The investigated molecular structures include molecular weight (Mw), molecular weight distribution, long chain branch amount and distribution and short chain branch among and along polyethylene chains. The long chain branches concentration was quantified using gel permeation chromatography and short branches concentration using nuclear magnetic resonance techniques. The adhesion strength was measured immediately after melt bonding using a T-Peel test. The results showed that increasing Mw resulted in higher adhesion strength in linear metallocene ethylene α-olefins. Low long chain branch concentrations hinder reptation motion and diffusion, and result in lower adhesion strength. Low density polyethylene with highly branched chains yielded very low self-adhesion. A drastic difference in adhesion strength between metallocene and conventional linear low density polyethylene is attributed to homogeneity versus heterogeneity of composition distribution. The low interfacial self-adhesion in conventional polyethylene was concluded to be due to enrichment of highly branched low molecular weight chains at the film surface. These segregated chains at the interface diffuse before the high molecular weight chains located in the bulk.

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Different Dependence of Tear Strength on Film Orientation of LLDPE Made with Different Co-Monomer

Polymers ◽

10.3390/polym11030434 ◽

2019 ◽

Vol 11 (3) ◽

pp. 434 ◽

Cited By ~ 3

Author(s):

Yi Ren ◽

Ying Shi ◽

Xuerong Yao ◽

Yujing Tang ◽

Li-Zhi Liu

Keyword(s):

Molecular Weight ◽

Crystal Orientation ◽

Low Density Polyethylene ◽

Low Density ◽

Linear Low Density Polyethylene ◽

Machine Direction ◽

Tear Strength ◽

Similar Dependence ◽

Similar Density ◽

Shrinkage Property

Crystal orientations, tear strength and shrinkage of Linear Low-Density PolyEthylene (LLDPE) films made with different processes (compressed, cast and blown) were investigated. The films were made with three different LLDPE resins, respectively, which have similar density and molecular weight but are made with different comonomers (1-butene, 1-hexene and 1-octene), in order to investigate if tear strength in Machine Direction (MD) of the LLDPE films made with different comonomer has similar dependence on crystal orientation. Our study indicates that the films made of 1-hexene and 1-octene based LLDPE resins have significantly higher intrinsic tear strength and less decrease in MD tear strength for a given film orientation. That is, for a given orientation in MD, the MD tear drops dramatically for films made with butene-based resin but much less decrease for the films made with hexene and octene-based resins. The shrinkage property at high temperature shows a good correlation with crystal orientation and the fraction of the crystals melted at this temperature.

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Solubility of Antioxidants in Rubber

Rubber Chemistry and Technology ◽

10.5254/1.3538410 ◽

1996 ◽

Vol 69 (5) ◽

pp. 885-896 ◽

Cited By ~ 6

Author(s):

S. A. Pushpa ◽

P. Goonetilleke ◽

N. C. Billingham

Keyword(s):

Molecular Weight ◽

Melting Point ◽

General Rule ◽

Low Density Polyethylene ◽

Phenolic Antioxidants ◽

Low Density ◽

Temperature Dependent

Abstract Solubilities of seven phenolic antioxidants in rubber and three antioxidants in low density polyethylene (LDPE) were measured at temperatures ranging trom 40°C–100°C. The antioxidants are more soluble in rubber than in LDPE, which is semicrystalline. The solubility of antioxidants is temperature dependent and both the melting point of the additive and its interactions with the polymer are important in determining solubility. As a general rule, solubility decreases with increasing molecular weight.

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