The microporous poly(l-lactic acid) (PLLA) was prepared successfully by uniaxial stretching PLLA with nanoscale dispersed silica as pore forming agent. The SEM results revealed that the silica dispersed uniformly in the PLLA matrix with the form of monodispersed nanoparticles or nanoscale aggregates when the content was 3–20 wt%. The number and size of the micropores and the porosity for the microporous PLLA were increased with the increase of silica content, stretching ratio and stretching rate (5–20 mm/min), while were reduced with the rise of stretching temperature. The stretching ratio of 2.5 was the key point for pore forming when silica content was under 10 wt%. The porosity was up to 21.1% with the silica content of 20 wt% and stretching ratio of 4.5. The mechanical properties and thermal insulation properties of microporous PLLA were also improved comparing with that of PLLA without pores.

微孔聚（l纳米分散的二氧化硅作为成孔剂，通过单轴拉伸PLLA，成功制备了β-乳酸（PLLA）。SEM结果表明，当含量为3–20 wt％时，二氧化硅以单分散的纳米颗粒或纳米级聚集体的形式均匀地分散在PLLA基质中。微孔PLLA的微孔数量和尺寸以及孔隙率随二氧化硅含量，拉伸比和拉伸速率（5-20​​ mm / min）的增加而增加，而随着拉伸温度的升高而减小。当二氧化硅含量低于10wt％时，拉伸比为2.5是孔形成的关键点。孔隙率高达21.1％，二氧化硅含量为20 wt％，拉伸比为4.5。