In situ fibrillation of poly(trimethylene terephthalate) in polyolefin elastomer through multistage stretching extrusion

Abstract

Polyolefin elastomer (POE)/poly(trimethylene terephthalate) (PTT) microfibrillar composites (MFCs) were successfully fabricated by multistage stretching extrusion with an assembly of laminating‐multiplying elements (LMEs). The morphologies of these novel materials were greatly influenced by the compositions. The number of microfibrils increased with increasing PTT concentration, as revealed by scanning electron microscopy. The tensile strength was the highest along the extrusion direction at the weight ratio of 85/15. Moreover, dynamic rheological results showed that the storage modulus, loss modulus, and complex viscosity were the highest while the tan δ was the lowest for MFCs prepared at the weight ratio 85/15 compared with the neat POE, especially at low frequency (ω < 1 rad/s). In addition, the PTT microfibrils had more effect on the rheological properties compared to the PTT particles. However, the differences became negligible at high frequency (ω > 100 rad/s). © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43797.

The crystallization and rheological behaviors of in situ microfibrillar isotactic polypropylene/polyamide 66 composites with a selective β‐nucleating agent distribution

“…The in situ microfibrillar composites with iPP as matrix and x-PA66 as dispersed fibrils were fabricated through multistage stretching extrusion with an assembly of laminatingmultiplying elements (LMEs), the mechanism of which has been described in other literatures. [23][24][25] iPP and x-PA66 pellets with constant weight ratio of 85/15 were firstly dry-mixed in a high-speed mixer, then went through the two-screw extruder, connector, LMEs, and finally formed a sheet about 0.4 mm thick and 300 mm wide. The temperature profile from feed section to metering section of the twin-screw extruder was set at 150 C, 260 C, 265 C, 275 C, respectively.…”

In situ fibrillation of isotactic polypropylene in ethylene‐vinyl acetate: Toward enhanced rheological and mechanical properties

“…As schematically shown in Figure , when the polymeric melt enters into a LME, the flowing behavior can be described as follows: (1) dividing, the melt is first sliced into left and right parts; (2) stretching, the left and right parts then enters into two fish‐tail ducts, respectively, in which a strong shearing and elongational forces have been imposed on the melt; (3) multiplying, the two parts integrate into one at the exit of LME. An array of elaborate work launched by our research group indicated that LME could transform the spherical phase morphology into microfibrillar, which provided an effective route to obtain MFCs …”

Improved viscoelastic, thermal, and mechanical properties of in situ microfibrillar polypropylene/polyamide 6,6 composites via direct extrusion using a triple-screw extruder

“…Recently, in situ brillation of polymer blend, which converts the dispersed particles into micro-or nano-brillar structure, has attracted much attention. [3][4][5][6][7][8] Owing to the exibility and high aspect ratio, the brils can deform adequately in response to interbrillar interactions during ow. 9 When the brils concentration exceeds a certain value, the deformed brils can form a physical network structure which renders the blends excellent properties.…”

“…The enhanced melt elasticity is very important for some processing such as blow molding and foaming, where biaxial strength is needed. 11 Dong et al 6 observed that the poly(trimethylene terephthalate) (PTT) microbrils had a greater inuence on the rheological properties of polyolen elastomer (POE) than PTT particles because the PTT microbrils could form a physical network within the POE matrix. Zhao et al 10 and Wang et al 8 prepared in situ MFCs with different methods and measured the effects of dispersed phase concentration on the complex viscosity.…”

“…23 Different MFC systems have been studied to demonstrate the signicant effect of brillar structure on the properties of the polymer matrix, including PLA/PA, 11 PP/PET, 12,20 PE/PP 16 and POE/PTT. 6 In these studies, bril concentration was taken as the governing factor affecting the formation of a brillar network. However, it is well known the network structure is not only dependent on the bril concentration, but also on the brillar morphology such as its dispersion, diameter, aspect ratio, and deformability.…”