Poly nucleating agents

In addition to the nucleating agents discussed in Section 18.4, many other materials have been found to be effective. Whilst the nylons may be self-nucleating, partieularly if there is some unmelted crystal structure, seeding with higher melting point polymers can be effective. Thus nylon 66 and poly(ethylene terephthalate) are reported to be especially attractive for nylon 6. 

Sodium ionomers are commercially recognized as the most effective nucleating agents for PET compounds. The typical use rate of sodium ionomer-based nucleating agents is 3-4 wt%. The sodium salt of poly(ethylene-co-methacrylic acid) is a particularly effective nucleating agent for PET. 

Improvements of clarity in transparent materials can be obtained in a variety of ways. If unplasticized poly(vinyl chloride) includes an impact modifier with refractive index matching that of the polymer it is possible to use thinner sections and so increase clarity, rates of output, and gloss. With polyolefins, similar results may be achieved by including a nucleating agent to accelerate crystallization even polypropylene, which normally is translucent, thus can be made in an almost clear form. 

A comfortable pathway for improvement of the crystallization of poly(3-hydroxybutyrate) in a melt-spinning process is the use of nucleating agents like electron-beam irradiated PHB [28] or the reactive extrusion with peroxide [29]. 

It is not only the crystallization rate, however, which is influenced by nucleating agents, but also the morphology. Isotactic poly(propylene) crystallizes monoclinically in the presence of / -/-butyl benzoic acid and pseudohexagonally when the quinacridone dyestuff. Permanent Red EBB, is added. 

Kawamoto, N., Sakai, A., Horikoshi, T. et al. (2007) Nucleating agent for poly(L-lactic acid)-An optimization of chemical structure of hydrazide compound for advanced nucleation ability. Journal of Applied Polymer Science, 103, 198-203. 

Tsuji, H., Takai, H. and Saha, S.K. (2006) Isothermal and non-isothermal crystallization behavior of poly(L-lactic acid) Effects of stereocomplex as nucleating agent. Polymer, 47, 3826-3837. 

Wanamaker, C.L., Tolman, W.B. and Htilmyer, M.A. (2009) 2-Biopolymers poly(D-lactide)-poly(menthide)-poly(D-lactide) triblock copolymers as crystal nucleating agents for poly(L-lactide). Macromolecular Symposia, 283-284,130-138. 

Tsuji, H., Tashiro, K., Bouapao, L. and Narita, 1. (2008) Poly(glycolide) as biodegradable nucleating agent of poly(L-lactide). Macromolecular Materials and Engineering, 293,947-951. 

Kang, K.S., Lee, S.I., Lee, T.l. et al. (2008) Effect of biobased and biodegradable nucleating agent on the isothermal crystallization of poly (lactic acid). Korean Journal of Chemical Engineering, 25, 599-608. 

Xiao, H., Yang, L., Ren, X. et al. (2010) Kinetics and crystal structure of poly(lactic acid) crysttiUized nonisothermaUy Effect of plasticizer and nucleating agent. Polymer Composites, 31, 2057-2068. 

Bai, H., Zhang, W., Deng, H. et al. (2011) Control of crystal morphology in poly(L-lactide) by adding nucleating agent. Macromolecules, 44, 1233-1237. 

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