Rajen M. Patel

Theoretical prediction of tie‐chain concentration and its characterization using postyield response

In the past, relative tie-chain concentration has been semiquantitatively characterized by infrared dichroism on a stretched sample and from brittle fracture strenght. The probability of tie-molecule formation has also been theoretically estimated from chain dimensions and the semicrystalline morphology of the polymers. In this article the probability of tie-chain formation of monodisperse and homogeneous single-site ethylene copolymers has been estimated over a range of densities and molecular weights using the model proposed by Huang and Brown. The relative tie-chain concentration is obtained by multiplying tie-chain probability with the volume fraction crystallinity of polymer. A modified rubber elasticity theory is applied to calculate the concentration of chain links between junction points (crystallites) of the INSITE technology polymers (ITPs) from measured rubber modulus. It is expected that the chain-link concentration should relate to the tie-chain concentration. The calculated rubber modulus, or the chain-links concentration, of the ITPs increases with an increase in density in the 0.865 to 0.910 g/cc range and did not change significantly in the density range of about 0.91 g/cc to 0.954 g/cc. Normalized rubber modulus and relative tie-chain concentration data shows that the relative tie-chain concentration predicated by Huang and Brown model and measured using the modified rubber elasticity theory are quantitatively similar below 0.01 g/cc density. However, above 0.91 g/cc density, the measured rubber modulus is influenced by additional tie-chain formation during deformation due to breakdown of crystallities and, hence, the discrepancy exists between the two methods of estimating relative tie-chain concentration.

A Blown Film Comparison Between Conventional Lldpe and Pop Polymers

The introduction of a new family of substantially linear poly olefin copolymers made using the Insite* technology process and marketed under the Affinity* Polyolefin Plastomer (POP) tradename offers polymers with different structure-fabrication-property relationships compared to conven tional linear low density polyethylene (LLDPE) polymers. The objective of this paper is to compare the blown fabrication characteristics of a constrained ge ometry catalyst technology (CGCT) polymer to a conventional LLDPE polymer with the similar melt index and density.

Blown Film Bubble Forming and Quenching Effects On Film Properties

The blown film process is a complex manufacturing process in which film properties are found to be greatly influenced by the fabrication vari ables from which the film was produced. This article will focus on the control of these variables to demonstrate the methods of process control used for op timization of film properties for a linear low density polyethylene (LLDPE). The influences of crystallinity and orientation of polymer molecules must be correlated to fabrication variables to provide insight as to why the film proper ties vary.

Advances in polyolefin-based spunbond and binder fibres

Abstract This chapter discusses recent advances in soft and abrasion resistant spunbond fabrics made from polyethylene and polypropylene resins. Advances in polyethylene resin design via blending polyolefin plastomers for broadening bonding window and improving abrasion resistance of spunbond fabrics are described. Advances in propylene based spunbond fabrics using blends with propylene based plastomers and elastomers for improved softness and drapeability are also presented. Properties of bi-component spunbond fabrics made from polypropylene core and polyethylene sheath, combining tensile strength and spinnability of polypropylene, and softness and drapeability of polyethylene are discussed. Finally, properties of bonded air-laid pads produced from cellulose and bi-component binder fibres having polyester cores and a blend of polyethylene and MAH-g-HDPE in the sheaths are described.

Advances in polyolefin-based fibers for hygienic and medical applications

Abstract This chapter discusses recent advances in soft and abrasion resistant spunbond fabrics made from polyethylene and polypropylene resins. Advances in polyethylene resin design via blending polyolefin plastomers for broadening bonding window and improving abrasion resistance of spunbond fabrics are described. Advances in propylene-based spunbond fabrics using blends with propylene-based plastomers and elastomers for improved softness and drapeability are also presented. Properties of bicomponent spunbond fabrics made from polypropylene core and polyethylene sheath, combining tensile strength and spinnability of polypropylene, and softness and drapeability of polyethylene are discussed. Finally, properties of bonded air-laid pads produced from cellulose and bicomponent binder fibers having polyester cores and a blend of polyethylene and MAH- g -HDPE in the sheaths are described.