Low density microcellular foams
    1.
    发明授权
    Low density microcellular foams 失效
    低密度微孔泡沫

    公开(公告)号:US4673695A

    公开(公告)日:1987-06-16

    申请号:US785436

    申请日:1985-10-08

    摘要: Low density, microporous polymer foams are provided by a process which comprises forming a solution of polymer and a suitable solvent followed by rapid cooling of the solution to form a phase-separated system and freeze the phase-separated system. The phase-separated system comprises a polymer phase and a solvent phase, each of which is substantially continuous within the other. The morphology of the polymer phase prior to and subsequent to freezing determine the morphology of the resultant foam.Both isotropic and anisotropic foams can be produced. If isotropic foams are produced, the polymer and solvent are tailored such that the solution spontaneously phase-separates prior to the point at which any component freezes. The morphology of the resultant polymer phase determines the morphology of the resultant foam and the morphology of the polymer phase is retained by cooling the system at a rate sufficient to freeze one or both components of the system before a change in morphology can occur. Anisotropic foams are produced by forming a solution of polymer and solvent that will not phase separate prior to freezing of one or both components of the solution. In such a process, the solvent typically freezes before phase separation occurs. The morphology of the resultant frozen two-phase system determines the morphology of the resultant foam.The process involves subjecting the solution to essentially one-dimensional cooling. Means for subjecting such a solvent to one-dimensional cooling are also provided.Foams having a density of less than 0.1 g/cc and a uniform cell size of less than 10 .mu.m and a volume such that the foams have a length greater than 1 cm are provided.

    摘要翻译: 通过包括形成聚合物溶液和合适溶剂的方法提供低密度,微孔聚合物泡沫,然后快速冷却溶液以形成相分离系统并冷冻相分离系统。 相分离系统包括聚合物相和溶剂相,其各自在另一个内基本连续。 在冷冻之前和之后的聚合物相的形态决定所得泡沫的形态。 可以生产各向同性和各向异性泡沫。 如果产生各向同性泡沫,则定制聚合物和溶剂使得溶液在任何组分冻结的点之前自发相分离。 所得聚合物相的形态决定了所得泡沫体的形态,并且通过以足以在形态变化发生之前冻结体系的一个或两个组分的速率冷却系统来保留聚合物相的形态。 通过形成聚合物和溶剂的溶液来产生各向异性泡沫,该溶液在溶液的一个或两个组分冷冻之前不会相分离。 在这种过程中,溶剂通常在相分离发生之前冻结。 所得冷冻两相体系的形态决定所得泡沫的形态。 该方法包括使溶液基本上进行一维冷却。 还提供了使这种溶剂进行一维冷却的方法。 具有小于0.1g / cc的密度和小于10μm的均匀泡孔尺寸的泡沫和具有长度大于1cm的泡沫的体积。