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David Richman

Bio: David Richman is an academic researcher. The author has contributed to research in topics: Diffusion (business) & Molecular diffusion. The author has an hindex of 2, co-authored 2 publications receiving 287 citations.


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Book ChapterDOI
Hiroshi Fujita1
01 Mar 1961
TL;DR: In this article, the authors discuss some selected topics with which they have a relatively greater acquaintance but which they feel are of fundamental importance for understanding the current situation in this field of polymer research.
Abstract: Introduction The diffusion of small molecules in polymeric solids has been a subject in which relatively little interest has been shown by the polymer chemist, in contrast to its counterpart, i.e., the diffusion of macromolecules in dilute solutions. However, during the past ten years there has been a great accumulation of important data on this subject, both experimental and theoretical, and it has become apparent that in many cases diffusion in polymers exhibits features which cannot be expected from classical theories and that such departures are related to the molecular structure characteristic of polymeric solids and gels. Also there have been a number of important contributions to the procedures by which diffusion coefficients of given systems can be determined accurately from experiment. I t is impossible, and apparently beyond the author's ability, to t reat all these recent investigations in the limited space allowed. So, in this article, the author wishes to discuss some selected topics with which he has a relatively greater acquaintance but which he feels are of fundamental importance for understanding the current situation in this field of polymer research. Thus the present paper is a kind of personal note, rather than a balanced review of diverse aspects of recent diffusion studies.

752 citations

Journal ArticleDOI
01 May 1978-Polymer
TL;DR: In this article, a model involving a linear superposition of one or two phenomenologically independent first order relaxation terms upon the ideal Fickian diffusion equation was proposed to describe the individual contributions of the diffusion and relaxation processes.

575 citations

Journal ArticleDOI
TL;DR: The authors reviewed recent findings on wood-water interaction and put them into context of established knowledge in the field, and several new findings challenge prevalent theories and are critically discussed in an attempt to advance current knowledge and highlight gaps.
Abstract: This paper reviews recent findings on wood–water interaction and puts them into context of established knowledge in the field. Several new findings challenge prevalent theories and are critically discussed in an attempt to advance current knowledge and highlight gaps. The focus of this review is put on water in the broadest concept of wood products, that is, the living tree is not considered. Moreover, the review covers the basic wood–water relation, states and transitions. Secondary effects such as the ability of water to alter physical properties of wood are only discussed in cases where there is an influence on state and/or transition.

429 citations

Journal ArticleDOI
TL;DR: The kinetics of drug release from hydrogel matrices will be examined both experimentally and theoretically and special emphasis will be placed on the effect of local drug concentration on the swelling behavior ofhydrogel drug carriers.

353 citations

Journal ArticleDOI
TL;DR: In this paper, the authors define Fickian diffusion in rubbery polymers and present a review and classification of various theoretical models which have been proposed to account for these phenomena.
Abstract: After defining Fickian diffusion in rubbery polymers an overview of transport behavior in polymers is presented. Diffusion and sorption below the glass transition are discussed, followed by a review and classification of the various theoretical models which have been proposed to account for these phenomena. A short list of recommendations for future work is included.

315 citations