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Microscale Property Control on Polymer films by Utilizing Interfering Laser Heating

利用干涉激光加热对聚合物薄膜进行微尺度性能控制

基本信息

批准号：
10450081
负责人：
SATOH Isao
金额：
$ 7.42万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

In this research project, we focused attention to the microscale property control by using an interfering IR radiation. As the first step, birefringence in skin-layers of an injection-molded polymer strip was controlled as a "pattern" by irradiation of interfered IR laser. Controllability of the birefringence pattern was experimentally examined, and the results showed that (1) an evident birefringence pattern, spacing of which is less than 70 μm, can be "recorded" on the skin-layer by the interfered IR irradiation, and that (2) the minimum spacing of the recordable birefringence pattern is influenced by the molding conditions, such as melt temperature and velocity, mold wall temperature, and radiation intensity. In order to investigate the relation between the pattern recordability and temperature distributions in the polymer melt, heat transfer within the melt was numerically estimated under the interfered IR laser irradiation condition. The results showed that (3) the temperature distributions within the skin-layer correspond well with the birefringence pattern recorded on the polymer strip, and that (4) thermal diffusion within the polymer obstructs the recording of birefringence pattern especially when the pattern spacing becomes narrower. Applying the basic findings obtained, molecular orientation in a polymer film was controlled by using the interfered IR irradiation as the second step. The birefringence pattern was recorded also on the film as same manner as the injection-moldings by using the interfered IR irradiation, but it was shown that the irradiation condition for the film where the evident birefringence pattern can be recorded is more rigid than for the injection-molding. This is explained by the fact that cooling of the film by the surroundings is weaker than that of the injection-molding, and that the thickness of film is too thin to absorb irradiated IR energy in general; both of them result in "flat" temperature distribution within the film.

在这项研究项目中，我们专注于通过使用干涉红外辐射的微尺度性能控制。作为第一步，在注射成型的聚合物条的皮层中的双折射被控制为“图案”，通过照射干涉的IR激光。实验结果表明：（1）干涉红外辐射可以在皮层上“记录”出间距小于70 μm的明显双折射图案;（2）可记录双折射图案的最小间距受成型条件的影响，如熔体温度、熔体速度、模壁温度、和辐射强度。为了研究图案可记录性与聚合物熔体中温度分布之间的关系，在干涉红外激光照射条件下，对熔体内的传热进行了数值估计。结果表明：（3）皮层内的温度分布与记录在聚合物条带上的双折射图案具有良好的对应关系;（4）聚合物内部的热扩散阻碍了双折射图案的记录，尤其是当图案间距变窄时。应用所获得的基本发现，通过使用干涉红外辐射作为第二步来控制聚合物膜中的分子取向。通过使用干涉IR照射，也以与注塑成型相同的方式在膜上记录双折射图案，但是显示出，可以记录明显的双折射图案的膜的照射条件比注塑成型更严格。这是由以下事实来解释的：由周围环境对膜的冷却弱于注塑的冷却，并且膜的厚度太薄而不能吸收辐射的IR能量;这两者都导致膜内的“平坦”温度分布。