When polymer chains crystallize from melt, the folded-chain crystals (FCCs) spontaneously form into spherulite structure. Such FCC can be often tensile drawn into extended-chain crystals (ECCs) giving high mechanical properties, thus various drawing technique have been applied for semi-crystalline polymers. In contrast, some polymers having high melt viscosity can be tensile drawn even from amorphous melt, giving characteristic shish-kebab structure composed of ECCs formed during melt-drawing FCCs formed during cooling after drawing. In this review, the results of thermal analyses for melt-drawn membranes of three crystalline polymers, ultra-high molecular weight polyethylene, polytetrafluoroethylene and poly(tetramethyl-p-silphenylenesiloxane), were compared. From these results, melting behavior can reasonably characterize crystalline and phase structure of melt-drawn membrane.
Keywords:folded-chain crystals, extended-chain crystals, melt-drawing
Publication Date: 2026-01-25