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Nucleating agents for injection molded biopolymers.

机译：用于注塑生物聚合物的成核剂。

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摘要

The cooling time is an important economical parameter during plastics processing. For biopolymers such as PLA, the cooling rate is low due to a slow crystallization. A focus of this study was to evaluate the effect of different nucleating agents on biopolymers such as PLA and PSM to increase their crystallization rates and thermal diffusivity and to also reduce the half life time in isothermal crystallization and an in-mold thermal diffusivity measurement test. Isothermal crystallization tests of PLA with different nucleating agents (CaCO3, TiO2, BN, Mica, Talc, PSM, aliphatic-aromatic polyester BiomaxRTM 100) were studied. A faster crystallization rate reduces cooling time and increases productivity during a molding process. The maximum crystallinity of 34% was obtained by blending CaCO3 as a nucleating agent. The crystallization rate of PLA is maximum at 105°C and decreases above and below that temperature. PLA with a nucleating agent shows a two dimensional disk shaped crystal growth as predicted from the Avrami experiment.; Thermal properties are also important since they affect the cooling rate. The thermal diffusivities of PLA and PSM were measured using an in-mold method. PSM has a higher thermal diffusivity compared to PLA. PLA with Biomax RTM as a nucleating agent showed an increase in the thermal diffusivity in the amorphous or melt state but it did not affect the thermal diffusivity in the semi-crystalline or solid state.
机译：在塑料加工过程中，冷却时间是重要的经济参数。对于生物聚合物，例如PLA，由于结晶缓慢，因此冷却速率低。这项研究的重点是评估不同成核剂对生物聚合物（如PLA和PSM）的影响，以提高它们的结晶速率和热扩散率，并减少等温结晶的半衰期和模内热扩散率测试。研究了使用不同成核剂（CaCO3，TiO2，BN，云母，滑石，PSM，脂族-芳族聚酯BiomaxRTM 100）的PLA的等温结晶测试。更快的结晶速度减少了冷却时间，并提高了成型过程的生产率。通过混合CaCO3作为成核剂，获得最大结晶度为34％。 PLA的结晶速率在105°C时最大，在该温度之上和之下均会降低。如Avrami实验所预测的，具有成核剂的PLA显示出二维盘状晶体生长。热性能也很重要，因为它们会影响冷却速度。使用模内法测量PLA和PSM的热扩散率。与PLA相比，PSM具有更高的热扩散率。以Biomax RTM为成核剂的PLA在非晶态或熔融态下显示出热扩散率的增加，但在半结晶态或固态下却不影响其热扩散率。

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  • 作者

    Patel, Bhavin.;

  • 作者单位

    University of Massachusetts Lowell.;

  • 授予单位 University of Massachusetts Lowell.;
  • 学科 Engineering Materials Science.; Plastics Technology.
  • 学位 M.S.Eng.
  • 年度 2008
  • 页码 72 p.
  • 总页数 72
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 工程材料学;整形外科学（修复外科学）;
  • 关键词

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