Poly(lactic acid) (PLA) was modified using dicumyl peroxide (DCP) and tetraglycidyl diamino diphenyl methane (TGDDM) to improve its melt viscosity and molecular weight for a variety of industrial applications. The PLA was branched or crosslinked with DCP at 180 °C, and gel content was detected as the DCP concentration was over 0.6 phr. However, for TGDDM, it was observed that only chain extension or branching occurred; the number- and weight-average molecular weights and polydispersity index (PDI) increased. The melt flow index decreased as the concentration levels of DCP and TGDDM increased. However, when the TGDDM was over 0.5 phr, the opposite results were observed. The variations in the mechanical properties of modified PLA were marginal; however, the elongation at break slightly decreased. The onset value of the decomposition temperature of the DCP-modified PLA slightly decreased. In contrast, with TGDDM, the onset value slightly increased. As the branching and crosslinking of the modified PLA increasingly occurred, relatively low relaxation enthalpy was detected. However, the glass transition temperature (T_g) was not influenced. An increase in the storage modulus (G′), loss modulus (G″), and complex viscosity (η^*), and a decrease in tan δ at low frequencies showed that the rheological behavior of the modified PLA turned from liquid-like to solid-like because of the modifications achieved using DCP and TGDDM.

使用过氧化二枯基（DCP）和四缩水甘油基二氨基二苯甲烷（TGDDM）对聚乳酸（PLA）进行了改性，以提高其熔体粘度和分子量，可用于多种工业应用。在180°C下，PLA与DCP分支或交联，并且当DCP浓度超过0.6 phr时，检测到凝胶含量。然而，对于TGDDM，观察到仅发生扩链或支化。数均和重均分子量以及多分散指数（PDI）增加。熔体流动指数随着DCP和TGDDM浓度的增加而降低。但是，当TGDDM超过0.5 phr时，观察到相反的结果。改性PLA的机械性能变化很小；但是，断裂伸长率略有下降。DCP改性的PLA的分解温度的起始值略有下降。相反，对于TGDDM，起始值略有增加。随着改性PLA的支化和交联越来越多，检测到相对较低的弛豫焓。但是，玻璃化转变温度（T_g）不受影响。在低频下，储能模量（G'），损耗模量（G''）和复数粘度（η ^*）的增加以及tanδ的降低表明改性的PLA的流变行为从液态转变为液态。由于使用DCP和TGDDM进行了修改，因此呈实心状。