Structures of Membrane-forming Substances

Considerable progress has been made towards understanding the chemical and physical structures of many of the polymers or condensation polymers whose permeability will be discussed. One method of attack, which has been purely chemical, has been to investigate the stages in which the polymer can be synthesised or broken down. It is found that one may have polymerisation or condensation polymerisation into chains, plates, or three-dimensional networks. The family of linear or chain x olymers is a large one including Natural and synthetic rubbers. 

Among platy substances one may include such naturally occurring inorganic condensation polymers as 

Bakelites and similar infusible insoluble resins. Certain urea formaldehyde resins. 

Polystyrene chain Fusible resin chain (novolaks) 

In Figs. 136 and 136 are illustrated diagrammatioally the manner in which certain linear and three-dimensional polymers are built up. These diagrams have of course nothing to say concerning the spatial relationships of the various chains with 

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