In ancient times, wine was stored in soft bags of sheepskin. The problem was that as the skins aged, they became rigid and brittle.

在古时，酒是盛在软的羊皮袋里，但当羊皮老化后，便会变得僵硬和易碎坏。

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Polyurethane membranes modified with silk fibroin protein(SF) and silk fibroin peptide(SP) had good flexibility. They could overcome rigid and brittle weaks of SF membrane.

用丝素蛋白或丝素肽表面改性的聚氨酯膜表现出良好的柔韧性，它能够克服丝素膜刚而脆的弱点；

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