Off-campus UMass Amherst users: To download campus access theses, please use the following link to log into our proxy server with your UMass Amherst user name and password.

Non-UMass Amherst users: Please talk to your librarian about requesting this thesis through interlibrary loan.

Theses that have an embargo placed on them will not be available to anyone until the embargo expires.

Access Type

Open Access

Degree Program

Polymer Science & Engineering

Degree Name

Thesis (M.S.)

Year Degree Awarded



Three low density polye thylenes , one long branched (A) and two linear (B and C), have been solid-state extruded at different temperatures from ambient to 80°C and to draw ratios _< 8. The densities and melt indices of A, B and C are 0.920, 0.920 and 0.935 g/cm3 , and 1.9, 0.8 and 1.2 respectively. Melt crystallized billets were extruded through conical dies in an Instron Capillary Rheometer. The linear polymers draw more easily than the branched. All three strain-harden. Density, birefringence, tensile and thermal properties have been evaluated as functions of extrusion temperature and draw ratio. Despite some loss through die swell, substantial orientation takes place during solid-state extrusion as evidenced by increases in transparency, birefringence, tensile modulus (up to 4.5 times that of the original isotropic polymer) and thermal conductivity. No ma j or changes in crystallinity were observed as assessed by density and DSC measurements. Depending on the polymer and the draw temperature, density does go through a minimum or shows a monotonic increase with draw.