Preparation of ultra high molecular weight polyethylene morphologies of totally fused particles with superior mechanical performance

A method for making an isotropic homogeneous semicrystalline morphology of ultra-high-molecular-weight polyethylene comprising;

• heating an original powder stock or a partially fused melt-crystallized stock having granular memory, to a temperature between 220.degree. C. and 320.degree. C. in the absence of oxygen at a compression load of about 1500-2000 pounds for about ten minutes,
• then at about 150.degree. C. placing the material under a compression load of about 12000-14000 pounds for another ten minutes to provide a melt in which the stock fuses completely and loses memory of its former granular structure, and
• cooling the resultant material to ambient temperatures under a compression load of about 1500 pounds to give a semicrystalline morphology which has no memory of the granular nature of the original stock.

A method for making an anisotropic morphology of ultra-high-molecular-weight polyethylene comprising:

• heating an original powder stock or a partially fused melt-crystallized stock having granular memory to a temperature and for a time to fuse the stock completely and lose memory of its original granular structure,
• cooling the resultant material to ambient temperatures under compression to provide an initial homqgenous isotropic semicrystalline morphology which has no memory of the granular nature of the original stock, and
• solid-state deforming that semicrystalline morphology at a temperature near but below its crystalline melting point at a deformation ratio of about 5 to 8.

An isotropic semicrystalline morphology of ultra-high-molecular-weight polyethylene comprising a completely fused ultra-high molecular weight polyethylene without any memory of a granular structure.

An isotropic semicrystalline morphology of ultra-high-molecular-weight polyethylene obtained from a homogeneous melt of ultra-high molecular weight polyethylene with weight average molecular weight of several millions without the aid of radiation dopants.

A homogeneous melt crystallized ultra-high molecular-weight polyethylene morphology with an effective molecular network structure and number of physical entanglements without the aid of radiation cross linking or chemical cross linking agents.

An ultra-high-molecular-weight polyethylene useful for tendon fabrication, having a molecular weight of several million and made by

• first heating an original powder stock or a partially fused, melt-crystallized stock having a granular memory, to a temperature at which the stock fuses completely and loses memory of its former granular structure, and
• then cooling the resultant material to ambient temperatures under compression load to give a semicrystalline morphology without memory of the granular nature of the original stock.

An anisotropic morphology of ultra-high-molecular-weight polyethylene comprising:

• a solid-state deformed semicrystalline morphology, having no memory of a granular nature, deformed at a temperature near but below its crystalline melting point at a deformation ratio of about 5 to 8.

An ultra-high-molecular-weight polyethylene useful for tendon fabrication, having a molecular weight of several million and made by

• first heating an original powder stock or a partially fused, melt-crystallized stock having a granular memory, to a temperature at which the stock fuses completely and loses memory of its former granular structure,
• then cooling the resultant material to ambient temperatures under compression load to give a semicrystalline morphology without memory of the granular nature of the original stock, and
• then extruding the semicrystalline product through an extrusion rolling die at a temperature of about 130.degree. C. and at a deformation ratio of about 5-8.

An ultra-high-molecular-weight polyethylene useful for tendon fabrication, having a molecular weight of several million and made by

• first heating an original powder stock or a partially fused, melt-crystallized stock having a granular memory, to a temperature at which the stock fuses completely and loses memory of its former granular structure,
• then cooling the resultant material to ambient temperatures under compression load to give a semicrystalline morphology without memory of the granular nature of the original stock, and
• then drawing the semicrystalline product at a temperature of about 130.degree. C. and at a deformation ratio of about 5-8.