论文成果
Rheological properties and crystallization behavior of comb-like graft poly(L-lactide): influences of graft length and graft density
  • 点击次数:
  • 论文类型:期刊论文
  • 发表时间:2016-01-01
  • 发表刊物:RSC ADVANCES
  • 收录刊物:SCIE
  • 文献类型:J
  • 卷号:6
  • 期号:36
  • 页面范围:30320-30329
  • ISSN号:2046-2069
  • 摘要:Three series of narrowly dispersed comb-like graft poly(L-lactide) (PLLA) with controlled graft length and graft density have been facilely synthesized and characterized. The structural information was determined by means of H-1 NMR, GPC, and viscometry, demonstrating the well-defined grafted structure. The effects of grafting parameters on rheological properties, thermal and crystallization behaviors were investigated systematically to illustrate the structure-property relationships. By the analysis of the rheological behavior, the increase of graft length and graft density can both lead to an elevated value of zero-viscosity (eta(0)), enhanced complex modulus (G*) and increased complex viscosity (eta*). Comparatively, graft density contributes more to the improvement of rheological properties than graft length does. For thermal properties, DSC results show that the glass transition temperature (T-g), the melting temperature (T-m) and the crystallization enthalpy (Delta H-m) of graft PLLA increase with the chain length and decrease with the graft density. Furthermore, spherulite morphologies and growth rates were studied by polarized microscopy (POM), and the observation revealed a remarkable improvement of radius growth rate of the spherulites (G) when graft density increased. The results indicate that G depends more on the molecular weight of each arm (M-n,M-arm) than the total M-n.

上一条: Copolymerization of L-lactide/trimethylene carbonate by organocatalysis: controlled synthesis of comb-like graft copolymers with side chains with different topologies

下一条: Fully biobased thermoplastic elastomers: synthesis and characterization of poly(L-lactide)-b-polymyrcene-b-poly(L-lactide) triblock copolymers