Development and characterization of solid and porous polylactide‐multiwall carbon nanotube composites

Abstract

This article describes the fabrication of solid and porous polylactide (PLA)‐multiwall carbon nanotube (MWNT) composites prepared using melt blending and subsequent batch processing of porous structures. The morphology and thermal, rheological and electrical properties of the PLA‐MWNT composites prepared with MWNT concentrations of 0, 0.5, 1, 2, and 5 wt% were characterized. The composite structure consisted of identifiable regions of MWNT aggregation and MWNT dispersion. Increasing MWNT content was found to increase the thermal stability and crystallization kinetics of PLA. The addition of MWNT to PLA significantly increased the melt viscosity and electrical conductivity of the composites. Based on rheological and electrical measurements, a continuous MWNT network structure in PLA was found to form when the concentration of MWNT is increased from 0.5 wt% (0.33 vol%) to 1 wt% (0.66 vol%). As many current day applications of polymers and polymer composites require lightweight and low‐density materials, porous PLA‐MWNT composites were fabricated from a batch porous structure processing technique. Porous PLA‐MWNT composites containing 2 and 5 wt% MWNT had lower relative densities, which is attributed to the higher viscosity of the composites suppressing collapse of the porous structure during processing. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers

Effects of multi-walled carbon nanotubes on flame retardation and thermal stabilization performance of phosphorus-containing flame retardants in polypropylene

“…On the other hand, MFI value of the C2 sample is slightly higher than that of the blank sample, but increasing the amount of MWNTs loading leads to a decrease in MFI value so that the MFI value of C4 and C6 samples is slightly lower than that of the blank sample. Melt viscosity increase by the addition of carbon nanotube has been observed by others and is attributed to the formation of a continuous MWNTs network structure in the polymer [11]. Furthermore, by comparing MFI values of APC2, APC4, and AP15 samples, it could be inferred that the addition of MWNTs to AP15 sample leads to a decrease in MFI value which is proportional to the amount of value of MWNTs loading.…”

Electrospun nylon fibers for the improvement of mechanical properties and for the control of degradation behavior of poly(lactide)-based composites

“…Some applications of this approach to fiber-reinforced nanocomposites were recently reported. [7][8][9][10][11][12][13][14][15] Xiong and coworkers obtained the in situ formation of submicrometric poly(glycolic acid) fibrils within a PLA-co-poly(caprolactone) matrix, improving the shapememory properties of the composite obtained therefrom. 7 Yano and colleagues filled PLA with quantities up to 10% of fibrillated cellulose with submicrometric diameter, observing increases in tensile modulus and strength.…”

“…8 Carbon nanotubes (CNTs) are another example of suitable fibrous material for the preparation of nanocomposites, which, however, pose several problems in filler dispersion due to their tendency to bundle and aggregate. 9,10 By electrospinning, fibers with a nanometric diameter can be produced; thus, this is an ideal method for the production of nanosized fibrous fillers to be included in a polymer matrix, allowing to produce nanocomposites. However, electrospun nanofibers are mostly proposed for applications in fields such as nanocatalysis, tissue scaffolds, protective clothing, filtration, and optical electronics.…”

Physical Properties, Crystallization, and Thermal/Hydrolytic Degradation of Poly(L‐lactide)/Nano/Micro‐Diamond Composites

“…multi‐wall carbon nanotube (MWCNT),22–29 and graphene 30–39 are intensively investigated to improve mechanical properties 21, 25, 32, 38 and thermal/hydrolytic degradation‐resistance of PLA‐based materials 16, 20, 27, 32, 34, 39, 40 and to manipulate their hydrolytic degradation behavior. The carbon‐based nano‐structured fillers are known to increase the conductivity 16, 19, 24, 26–28, 38, 39 and accelerate the crystallization of PLLA,15–19, 23, 27, 30, 31, 33, 35, 37–39 which will elevate the crystallinity and thereby the thermal stability of PLA‐based materials, in addition to the effects of incorporated high hardness fillers. Moreover, carbon‐based nano‐structured fillers were utilized to give PLA‐based materials other functionalities such as sensors for volatile organic compounds,28 increased flame retardancy,31 accelerated bone regeneration,29 and increased biocompatibility 36…”