On the cutting mechanism of high polymers

Abstract

The characteristics of the cutting phenomena in linear high polymers, such as polytetrafluoroethylene, polystyrene, and poly(methyl methacrylate) are described in order to make clear the cutting mechanism which is available to produce high quality and accurate parts. Thus, the types of chips, the deformation of the work material, and the critical rake angle defined by the authors are described. Several discussions on the thermal, the time (or cutting speed), and the frictional dependencies are also described. The chips are divided into two main categories the continuous (curl, flow, and shear type) and discontinuous (crack and tear type). These are influenced by the kinds and temperature of the work materials, the rake angle of a tool, and the depth of the cut and cutting speed. It was clarified by the discussions that the viscoelastic behavior of the work material was important during cutting of high polymers. Therefore, the Voight and Maxwell Model were introduced to explain the time dependencies. We could say that the types of cutting mechanism of high polymers are classified as, slip on the shear plane, crack at the tip of a tool, tear at the cutting edge accompanied by heavy strain, and some combinations of these. Cutting with the critical rake angle (that is a rake angle which makes the thrust force during cutting equal to zero), the work material was neither deformed upwards nor downwards, thus the highest accuracy was obtained. Furthermore, the work material must be equal to the frictional angle of the rake surface of the tool, and was decided upon by the frictional behavior of the chip on the rake surface.

Effect of nanosectioning on surface features and stiffness of an amorphous glassy polymer

“…b and c. These structures oriented in parallel and were perpendicular to the sectioning direction. The patterns of the localized structures resemble those found by Black and Wang et al in metal sectioning as well as those observed by Kobayashi and Satio in polymer sectioning.…”

“…In this study, the spacing for the periodic bands is proportional to the sectioning thickness [23]. It ranged from 100 to 400 nm, much smaller than most of reported values in [17,18,26,28,29,39].…”

Aza‐Michael addition reaction: Post‐polymerization modification and preparation of PEI/PEG‐based polyester hydrogels from enzymatically synthesized reactive polymers

“…Itaconate‐based monomers can be obtained from natural resources and are shown to be useful building blocks in the preparation of a variety of biomaterials . A Candida antarctica lipase B catalyzed polyesterification between monomers 1 and 2 gave rise to the targeted PEG‐based polyester 3 carrying aza‐Michael acceptors placed along the polymer backbone . It was necessary to add a free‐radical inhibitor during the polymerization reaction to avoid material gelation due to the radical‐based crosslinking reaction of the itaconate segments.…”

Synthetic Methodologies for Chelating Polymer Ligands: Recent Advances and Future Development

“…The problems of ecology in the synthesis of CPLs are solved by the principles of «green chemistry», implemented by replacing environmentally hazardous substances with safer materials, increasing cycles of product biodegradation, using enzymatic catalysts and renewable resources to improve the safety and efficiency of polymer chemistry ,, . Thus, the enzymatic polymerization of phenol proceeds with a conversion of up to 99.1% in an environmentally friendly system, including tetra ‐butyl‐ammonium bromide .…”