Atsushi Aoshima

The effects of pressure on drawing polyoxymethylene: 2. Drawn fibre properties and structure

Abstract Superdrawn polyoxymethylene fibres produced by pressurized drawing are dense and transparent, and have good mechanical properties. Maximum tensile modulus and strength and apparent density were found to be 58 GPa, 2.0 GPa and 1.45 g cm −3 , respectively. A study was made of the effects of pressure on the mechanical properties and structural characteristics of drawn fibres. The relationship between these parameters is discussed.

The effects of pressure on drawing polyoxymethylene: 1. Processing

Abstract A new process has been developed for the continuous drawing of polymers under pressure. Draw ratios up to 34 were achieved by this process using polyoxymethylene. The pressure applied in the process acts effectively on the drawing behaviour, temperature, stress and velocity.

The effects of pressure on drawing polyoxymethylene: 3. Effects of voids on the chemical resistance of polyoxymethylene drawn fibres

Abstract Assessment was made of the chemical resistance of superdrawn polyoxymethylene fibres produced by pressurized drawing. The fibres were found to have good properties such as alkali, acid, thermal and weather resistance. The relation between these properties and fibre structure is discussed.

Effect of pressure on drawing poly(oxymethylene) fibres: 4. Heat shrinkage of annealed superdrawn fibres

The heat shrinkage of annealed transparent superdrawn poly(oxymethylene) fibres was quite small (even less than that of white fibres). This parameter is discussed in relation to fibre structural parameters such as void ratio, crystallinity, crystallite orientation and crystal size.

Analysis of voids in superdrawn polyoxymethylene fibres

Abstract Void factors (size and distribution) of polyoxymethylene superdrawn fibres were determined, and their relationship to tensile strength was examined. Microvoids ∼1 μm2 caused a decrease in tensile strength

Synthesis of perfluoropolyether with high molecular weight

Abstract Because of the mobile structure of the main chain, the polymer of hexafluoropropene oxide (HFPO) with high molecular weight is expected to be a new type of perfluoropolymer showing the flexibility and the low temperature workability, which are not observed for the perfluorocarbon type polymers such as polytetrafluroethene. In the polymerization of HFPO, however, the chain transfer reaction takes place easily to result in the formation of the viscous liquid oligomer with low molecular weight, at most. We investigated the method to prepare the polymer of HFPO with high moleculear weight by connecting the bifunctional oligomer of HFPO by means of a stable triazine group, as shown in Figure 1. Then, we established the method to form the polymer of HFPO with high molecular weight more than 1 × 10 6 , which is an elastic solid and is useful as a new type of advanced material. The details of the preparation method and the characteristics of this polymer will be presented. Figure 1. Approach to the HFPO Polymer with High Molecular Weight