The effect of seeding on the crystallisation of poly(hydroxybutyrate), and co-poly(hydroxybutyrate-co-valerate)
The effect of seeding on the crystallisation of poly(hydroxybutyrate), and co-poly(hydroxybutyrate-co-valerate)
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DOI：
10.1016/s0032-3861(98)00732-0
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发表时间：
1999-08
期刊：
影响因子：
4.6
通讯作者：
R. E. Withey;J. N. Hay
中科院分区：
文献类型：
--
作者：
R. E. Withey;J. N. Hay
为了提高聚羟基丁酸酯（PHB）和聚羟基丁酸酯-共戊酸酯（CHB/HV）的结晶速率，研究了各种晶种剂的影响。制备了含糖精或邻苯二甲酰亚胺的PHB固体混合物以及CHB/HV与PHB的共混物。将这些材料作为成核剂的效果与商业成核剂氮化硼（BN）进行比较。在评估相对引晶能力时，通过DSC和光学显微镜测量总体结晶速率、球晶发展和成核密度。FT-IR显微镜用于测定成核剂在熔融聚合物中的溶解度。结果表明，糖精和邻苯二甲酰亚胺作为成核剂的效果不如BN。它们在熔融的PHB中相对可溶，但被结晶的PHB排斥。糖精和邻苯二甲酰亚胺几乎没有成核作用，而糖精和邻苯二甲酰亚胺的小微晶在球晶的边界内发展，大部分材料积累在球晶之间的区域中。PHB作为CHB/HV的成核剂，但发现其活性并不上级于BN作为成核剂。
In order to enhance the rate of crystallisation of polyhydroxybutyrate (PHB), and copolyhydroxybutyrate-co-valerate (CHB/HV), the effect of various seeding agents was investigated. Solid mixtures of PHB containing either saccharin or phthalimide, and a blend of CHB/HV with PHB were prepared. The effect of these materials as nucleating agents was compared with a commercial nucleating agent, boron nitride (BN). In assessing the relative seeding abilities, overall crystallisation rate, spherulite development and nucleation density were measured by DSC and optical microscope. FT-IR microscopy was used to determine the solubility of the nucleating agent in the molten polymer. The conclusions are drawn that saccharin and phthalimide are much less effective as nucleating agents than BN. They are comparatively soluble in molten PHB but are rejected from the crystalline PHB. There was little nucleation by saccharin and phthalimide, and whilst small crystallites of saccharin and phthalimide develop within the boundaries of the spherulite much of the material accumulates in the regions between the spherulites. PHB acted as a nucleating agent for CHB/HV although the activity was not found to be superior to BN as the nucleating agent.