Largely reinforced polyurethane via simultaneous incorporation of poly(lactic acid) and multiwalled carbon nanotubes

Abstract

In this study, we simultaneously introduced both poly(lactic acid) (PLA) and multiwalled carbon nanotubes (CNTs) into the polyurethane (PU) matrix via melt blending, to achieve balanced mechanical properties and good conductivity. Different contents of PLA (0-30 wt%) and CNTs (0-3.0 wt%) were used in this work. A significant improvement in tensile strength at 300% strain and Young's modulus were observed, which could not be obtained by incorporating either PLA or CNTs with PU separately. Particularly, the ternary composites containing a large amount of PLA (30 wt%), 70PU/30PLA/CNTs composites, exhibit superior mechanical properties compared to other composites with less PLA content but the same amounts of CNTs. Moreover, the ternary composites showed better electrical conductivity compared with the binary counterpart. SEM observations demonstrated that PLA particles and CNTs are separately dispersed in the PU matrix. It was found that PLA particles remain spherical and their size increases with increasing PLA content up to 30 wt%, while a network structure of CNTs is formed with increasing its content, which was also confirmed via dynamic rheological analysis. Interestingly, some CNTs were seen to be located in the interfaces between PLA particles and the PU matrix for 70PU/30PLA/CNTs composites, namely, some CNTs exhibit a nano-bridge effect between PU and PLA. We hypothesized that the nano-bridge structure of CNTs in the composites could mainly contribute to the observed enhancement of mechanical properties and electrical conductivity.

High Modulus, Strength, and Toughness Polyurethane Elastomer Based on Unmodified Lignin

“…PU elastomers (PUe) have attracted much attention because of their high ductility, toughness, and good stability. , However, low stiffness and low strength limit their application, which is about 10 MPa for the Young’s modulus and 10–25 MPa for tensile strength. − A general strategy to reinforce PUe is by blending them with other polymers such as polycaprolactone and poly­(acrylic acid) or by incorporating inorganic/organic fillers, including graphene, carbon nanotubes (CNTs), et al , However, due to aggregation of the fillers, the improved modulus and strength at high filler content are also accompanied by reduction of ductility and toughness. , To facilitate a better dispersion, in situ polymerization of monomers that possess reactive functional groups is another approach. Lignin, with abundant phenolic and aliphatic hydroxyl groups that could readily react with isocyanates to form urethane linkage, is a good candidate for preparation of biobased high value-added products, , especially for PU materials.…”

“…1,2 However, low stiffness and low strength limit their application, which is about 10 MPa for the Young's modulus and 10−25 MPa for tensile strength. 3−6 A general strategy to reinforce PUe is by blending them with other polymers such as polycaprolactone and poly(acrylic acid) or by incorporating inorganic/organic fillers, including graphene, carbon nanotubes (CNTs), et al 7,8 However, due to aggregation of the fillers, the improved modulus and strength at high filler content are also accompanied by reduction of ductility and toughness. 4,6 To facilitate a better dispersion, in situ polymerization of monomers that possess reactive functional groups is another approach.…”

Facile Fabrication of PBS/CNTs Nanocomposite Foam for Electromagnetic Interference Shielding

“…[17,18] Several research have reported the effect of CNTs on the foaming behaviors of biodegradable nanocomposites. [4,[19][20][21][22] In one of our previous works, a simple, green foaming way was utilized to fabricate PLA/CNTs nanocomposite foam with an ultra-high volume expansion ratio (VER) of 49.6. [4] Furthermore, Huang et al prepared PBS/CNTs/PTFE ternary composite foam with admirable electrical conductivity (σ) via using "ball milling" and supercritical CO 2 (scCO 2 ) foaming processing.…”

Poly(sodium 4-styrenesulfonate) modified graphene for reinforced biodegradable poly(ε-caprolactone) nanocomposites

“…10,11 Therefore, extensive works have been done to incorporate graphene into various polymers and investigate the properties of the formed composites. [12][13][14][15][16] The dispersion state of graphene plays a vital role in the nal properties of the composites. Small addition could signicantly reinforce many properties of host polymers if in which graphene dispersed uniformly.…”