Tom Wyatt

An effective and simple process for obtaining high strength silkworm (Bombyx mori) silk fiber

This article describes a new process for strengthening natural silk fibers. This process is simple yet effective for mass production of high strength silk fibers, enabled by drawing at a lower temperature and immediately heat setting at a higher temperature. The processing conditions were investigated and optimized to improve the strength. Silk fibers drawn to the maximum ratio at room temperature and then heat set at 200 °C show best tensile properties. Some salient features of the resulting fibers are tensile strength at break reaching 533±10.2 MPa and Young’s modulus attaining 12.9±0.57 GPa. These values are significantly higher than those of natural silk fibers (tensile strength increased by 44 % and Young’s modulus by 135 %). Wide-angle X-ray diffraction and FTIR confirm the transformation of silk I to silk II crystalline structure for the fiber obtained from this process. DSC and TGA data also provide support for the structural change of the silk fiber.

Correction to: Fabrication of high-strength polyoxymethylene fibers by gel spinning

In the original article, the name of author Donggang Yao was misspelled. It is correct here.

Twist-film gel spinning of large-diameter high-performance ultra-high molecular weight polyethylene monofilaments

A twist-film gel spinning process was developed for large-diameter high-performance ultra-high molecular weight polyethylene (UHMWPE) monofilaments. By using polybutene as a spin-solvent, film twisting was demonstrated to be an effective method for solvent removal; approximately 70% of solvent contained in the gel film can be removed simply by film twisting. This mechanical solvent removal process also makes conventional solvent extraction proceed significantly faster. Besides improved solvent extraction efficiency, large-diameter high-strength UHMWPE monofilaments (with diameters of about 80 µm and strength exceeding 3.2 GPa) can be produced with this process, which is difficult to achieve using conventional processes. The capability of making large-diameter high-strength monofilaments may allow new products of UHMWPE to be developed in a number of high-performance applications.

Processing of Nanodiamond Loaded Poly(Lactic Acid) Co-Continuous Porous Structures

Porous poly(lactic acid) PLA materials are highly demanded as scaffolding templates in tissue engineering applications. In this study, a protocol for creating co-continuous porous PLA structures with nanodiamond (ND) as additive was investigated. First, a ternary blend of PLA/PS/ND was prepared with different mixing ratios under different mixing conditions. Next, a post annealing stage was applied to coarsen the phase structure. Finally, the PS phase was sacrificially extracted, leaving a porous matrix. The experimental results showed that ND can be an effective compatiblizer for increasing the miscibility between PS and PLA and reducing the phase size. It was further found that the post annealing conditions significantly affect the distribution of ND particles in the blend and finally in the porous PLA structure.Copyright