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Poly(trimethylene terephthalate)-poly(ethylene oxide terephthalate) block copolymer (PTG)/multiwalled carbon nanotubes (MWCNTs) composites were prepared via in situ polymerization. To improve the dispersion of MWCNTs in the PTG matrix, the poly(ethylene glycol)-grafted multiwalled carbon nanotubes (MWCNT-PEG) were produced by the 'graft to' method. The transmission electron microscopy observation demonstrated that a homogeneous dispersion of MWCNT-PEG was obtained. As a consequence, the percolation threshold for the rheology was around 0.5 wt% and the conductivity was ~1 wt%, respectively. Differential scanning calorimetry and polarized optical microscopy results confirmed that MWCNT-PEG can act as an effective heterogeneous nucleating agent. Interestingly, the effects of MWCNT-PEG on crystallization and melting of the poly(ethylene oxide terephthalate) blocks were more pronounced than on those of the PTT blocks. POLYM. ENG. SCI., 53:914-922, 2013. © 2012 Society of Plastics Engineers, INTRODUCTION Since the discovery of carbon nanotubes (CNTs) in 1991 by Iijima (1), the properties and application of carbon nanotubes and related materials have been very active research fields over [...]

In this article, the particular phase morphology of immiscible polyamide 12/polystyrene (PAl2/PS) blends prepared via in situ anionic ring-opening polymerization of laurolactam (LL) in the presence of polystyrene (PS) was investigated. Scanning electron microscopy (SEM) and Fourier Transform infrared Spectroscopy (FTIR) were used to analyze the morphology of the blends. The results show that the PS is dispersed as small droplets in the continuous matrix of PAl2 when PS content is 5 wt%. However, when the PS content is higher than 10 wt%, two particular phase morphologies appeared. Firstly, dispersed PS-rich particles with the spherical inclusions of PAl2 can be found when PS content is between 10 and 15 wt%. Then the phase inversion occurred (the phase morphology of the PAl2/PS blends changed from the PS dispersed/PAl2 matrix to PAl2 dispersed/PS matrix system) when PS content is 20 wt% or higher, which is unusual for polymer blends prepared via conventional methods such as mixing, hydrolytic polycondensation and so on. The formation of this particular phase morphology development was simply elucidated via a phase inversion mechanism. Furthermore, the stability of the phase morphology of the PAl2/PS blends after annealing at 230°C was also investigated via SEM. POLYM. ENG. SCI., 52:1831-1838, 2012. © 2012 Society of Plastics Engineers, INTRODUCTION The blending of miscible polymers for production of new tailor made materials at low cost has gained great interest in recent years, as this enables getting better mechanical properties [...]

Nylon 12 blends (BP) with nitrile-butadiene ultrafine full-vulcanized powdered rubber (NBUFPR) were successfully synthesized in a corotating intermeshing twin screw extruder via anionic ring-opening polymerization of lauryllactam at 250°C. The in situ formed blends were characterized by mechanical test, fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. A brittle-tough transition occurs when NBUFPR content is 4 wt%. And the notched Izod impact strength achieves 989 J [m.sup.-1] when 5 wt% NBUFPR was added. Because of the good dispersion property of NBUFPR during the process of reactive extrusion, the interparticle distance decrease remarkably. Besides, the in situ formed NBUFPR--PA12 leads to better adhesion between the two phases. For comparison, another series of blends (BL) were also prepared by melt blending hydrolytic-polymeric PA12 and NBUFPR in the same twin screw extruder. Brittle-tough transition did not appear in BL blends within the same range of NBUFPR content. POLYM. ENG. SCI., 50:1178-1185, 2010. [C]2010 Society of Plastics Engineers, INTRODUCTION The rapid anionic polymerization of lactams has received considerable attention since its discovery in the 1950s (1-27). Fast reaction kinetics, clean polymerization reaction without any by-products and a crystalline [...]