SPE Library
The SPE Library contains thousands of papers, presentations, journal briefs and recorded webinars from the best minds in the Plastics Industry. Spanning almost two decades, this collection of published research and development work in polymer science and plastics technology is a wealth of knowledge and information for anyone involved in plastics.
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Medical Plastics
Long- and Short-Term Tensile Strength and Morphology of Joined Beta-Nucleated Polypropylene Parts
Andrea Wübbeke, May 2020
This paper presents the results of static short-term and long-term tensile tests for beta-nucleated joined polypropylene samples by the hot plate welding process. In the present study different dimensionless joining displacements are accounted for. The results show that high short-term tensile strength does not directly transfer to high long-term tensile strength. The morphology of the weld seam in the joined samples is examined by means of transmitted and reflected light microscopy. For the dimensionless joining displacements of 0.75 and 0.95, stretched spherulites are obtained. X-Ray diffraction can be used as a tool for qualitative and quantitative analysis and eventually for differentiation of samples of various joining displacements.
Modeling of Heat Generation in Spin Welding
Miranda Marcus, May 2020
Spin welding is a common joining process for plastic parts with circular joints such as insulated cups and bowls, filter housings, and valves. In this process, heat is developed from surface friction as one part is revolved about the axis of the joint, resulting in a high linear speed. Finite element analysis (FEA) of the process can provide insight into potential mechanical deformation or failure under load that may compromise the weld, as well as aid in determining proper process parameters to achieve sufficient heating for a good weld. In this work, an approach to predict the weld temperature has been investigated and compared to measured results.
The Effect of Argon Plasma Irradiation On 3D Scaffolds For Bone Tissue Engineering
Katherine Wood, May 2020
Tissue engineering using 3D scaffolds is an alternative to bone repair techniques that are currently used, such as autografts or allografts for bone non-union. Plasma irradiation is used as a sterilization method and can alter the surface topography of the scaffolds. We have prepared 3D scaffolds composed of poly(lactic-co-glycolic)acid (PLGA) and nanohydroxyapatite (nHA) using thermally– induced phase separation (TIPS) and 3D-plotting (3DP) techniques. We have also performed experiments to study murine stem cell adhesion to scaffolds that have been plasma irradiated. The scaffolds that were plasma irradiated with argon gas had ~140% more cell adhesion compared to untreated scaffolds.
Windows of Opportunities for Single Site Catalyst
Prithu Mukhopadhyay, September 1999
What makes company A produce 50,000 tons/year more of the same PE or PP than company B at the same cost? Catalyst, catalyst and catalyst. Very quietly, catalyst research has brought revolution in the plastics industry. So-called single-site catalysts (many of which are metallocenes) are closely guarded secret of alpha-olefin "big guys". A single metal atom held between two carbon rings builds metallocenes. They might look naive but provide greater control over molecular chain length and structure of polyolefins. These polymers are stronger, purer, and clearer. Upon utilizing these catalysts, material suppliers can accurately design tailor-made resins for specific applications.
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