Diffusion and permeation of gases in undrawn and radially drawn films of native and commercial gutta-percha (trans-Polyisoprene)

The permeability of native and commercial grades of gutta-percha (trans-polyisoprene), was determined and related to diffusion rate both below and above the glass transition temperature (T_g) and the melting point (T_m). Both radially drawn and undrawn membranes were evaluated. Five gases (O₂, N₂, CO₂, H₂ and He) were used as permeants and the measurements were taken both above and below the polymers' crystalline T_m. The diffusivity of the gases was found to have an increased rate above the T_m. The reduction of solubility, diffusivity and permeability with increasing draw ratio was attributed to an increase in crystallinity.     

先进的湿法成形非织造技术

湿法成形非织造产品现今越来越显现出其重要性.这种工艺需要将原材料打碎成纤维,浸没于水中,然后在斜网部成形.本文介绍了Andritz Kiisters(安德里兹寇司德)公司neXformer wetlaid湿法成形机技术.安德里兹寇司德湿法成形生产线技术提供绝大部分应用领域的完整生产线方案,从浆料制备到neXformer湿法成形机到烘干、后整理和卷绕等.