High-density polyethylene semi-crystalline

Polyethylene is a major commodity plastic, with more than 33 billion pounds of the resin produced in the United States in 2000 [1]. Polyethylene encompasses a family of semi crystalline polymers with ethylene as the major building block [6]. The resins are loosely grouped into three classes low-density polyethylene (LDPE), high-density polyethylene (HD.PE), and linear-low-density polyethylene (LLDPE). LDPE is a homopoiymer of ethylene with side-chain branching at a frequency... 

Plasticity of two semi-crystalline poiymers high-density polyethylene (HDPE) and polyamide-6 (Nyion-6)... 

Bartczak, Z., Argon, A. S., Cohen, R. E., and Weinberg, M. (1999a) Toughness mechanism in semi-crystalline pol5mer blends I. High density polyethylene toughened with rubber, Polymer, 40, 2331-2346. 

The phase transition from disordered states of polymer melt or solutions to ordered crystals is called crystallization-, while the opposite process is called melting. Nowadays, more than two thirds of the global product volumes of synthetic polymer materials are crystallizable, mainly constituted by those large species, such as high density polyethylene (HOPE), isotactic polypropylene (iPP), linear low density polyethylene (LLDPE), PET and Nylon. Natural polymers such as cellulose, starch, silks and chitins are also semi-crystalUne materials. The crystalline state of polymers provides the necessary mechanical strength to the materials, and thus in nature it not only props up the towering trees, but also protects fragile lives. Therefore, polymer crystallization is a physical process of phase transition with important practical relevance. It controls the assembly of ordered crystalline structures from polymer chains, which determines the basic physical properties of crystalline polymer materials. 

High density polyethylene (HDPE) has balanced mechanical properties with good chemical resistance. It has better barrier properties against gases and vapors. It is also harder and stiffen The structure of HDPE is described as semi-crystalline [31]. LDPE is soft and flexible [32,33]. High density polyethylene has been identified as a primary material for solid waste minimization and recycling in blow molding. 

Polymer blends have proved another fruitful field for study, with considerable technological implications. Particularly simple, but commercially important, is the behaviour of a blend of low density polyethylene (LDPE) and high density polyethylene (HPDE a 50 50 blend of these two materials is semi-crystalline. In... 

Bartczak Z, Argon A S, Cohen R E and Weinberg M (1999) Toughness mechanism in semi-crystalline polymer blends II - High-density polyethylene toughened with calcium carbonate filler particles. Polymer 40 2347-2365. 

A considerable amount of work has been carried out to establish if it is possible to produce good-quality rubber/thermoplastic blends by incorporating waste rubber crumb, whether surface-activated or not, into thermoplastics matrices. This work has often been carried out using commodity semi-crystalline thermoplastics, such as low-density polyethylene (LDPE), high-density polyethylene (HOPE) and polypropylene (PP), with the aim to produce final products that are either modified (e.g., improvements in impact strength) or have properties that are usually associated with thermoplastic rubbers. 

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