A polymeric foam has a thermoplastic polymer matrix defining multiple cells, the foam characterized by: (a) the polymer matrix having greater than 50 weight-percent copolymer containing at least two different monomers at least one of which is a methacrylate monomer, each monomer having a solubility parameter lower than 20 (megaPascals)0.5 and a chemical composition where twice the mass fraction of oxygen plus the mass fraction of nitrogen, fluorine and silicon is greater than 0.2; wherein the monomers comprise at least 90 weight-percent of all monomers in the copolymer; (b) at least one of the following: (i) a nucleation site density of at least 3×1014 effective nucleation sites per cubic centimeter of foamable polymer composition; (ii) an average cell size of 300 nanometer or less; (c) a porosity percentage greater than 30%; (d) an absence of nano-sized nucleating additive; and (e) a thickness of at least one millimeter.
一种聚合泡沫具有热塑性聚合物基质,定义多个单元,其特征在于:(a)聚合物基质具有大于50重量百分比的共聚物,其中包含至少两种不同的单体,其中至少一种是
甲基丙烯酸酯单体,每种单体的溶解参数低于20(兆帕斯卡)0.5,
化学成分中氧的质量分数加上氮、
氟和
硅的质量分数的两倍大于0.2;其中单体占共聚物中所有单体的至少90重量百分比;(b)以下至少一种:(i)每立方厘米泡沫聚合物组成物中至少有3×1014有效成核位点密度;(ii)平均孔径小于300纳米;(c)孔隙率大于30%;(d)无纳米级成核添加剂;(e)厚度至少为1毫米。