Poly(lactic acid)/vermiculite‐g‐polyisoprene nanocomposites based on thiol‐ene click chemistry: performance, shear crystallization and Rheonaut technology analysis

Abstract

Vermiculite (VMT) grafted polyisoprene (PIP) (VMT‐g‐PIP) was synthesized by thiol‐ene click chemistry. An orthogonal experiment and range analysis showed that the optimum reaction parameters of VMT‐g‐PIP were as follows: reaction time 9 h, reaction temperature 60 °C, initiator azodiisobutyronitrile dosage 0.025 g and mass ratio of isoprene to VMT‐SH 3:1. Due to the strong interfacial compatibility between poly(lactic acid) (PLA) and VMT‐g‐PIP, the impact strength and elongation at break of PLA/VMT‐g‐PIP (0.7 wt%) nanocomposites were increased by 1.33 and 5.20 times, respectively, compared with pure PLA. Thermogravimetric analysis and cone calorimeter analysis demonstrated that the thermal stability and fire resistance effect of PLA/VMT‐g‐PIP nanocomposites had been improved to a certain extent. Differential scanning calorimetry and Rheonaut technology for simultaneous rheometry and Fourier transform infrared spectroscopy demonstrated that the synergistic effect of shear field and heterogeneous nucleation of VMT‐g‐PIP induced faster crystallization of PLA. Accordingly, the crystallization properties of PLA were clearly improved, which enhanced its toughness. Enzymatic degradation behavior showed that VMT‐g‐PIP inhibited the biodegradation of PLA to a certain extent. © 2021 Society of Industrial Chemistry.

Preparation, stretch‐induced crystallization and thermo‐oxidative aging behavior of poly (lactic acid)/saponite grafted polystyrene nanocomposites films

“…Figure 6A represents the full spectra of SAP and SAP‐g‐PS, from which could be seen that the C1s of unmodified SAP deconvolutes into three peaks, with characteristic peaks of Si2p, C1s and O1s at 102.7, 284.8 and 533 eV, respectively. As can be seen from Figure 6B, compared with the unmodified SAP, the C content was increased from 58.02% to 62.57%, and the O content of grafted styrene was significantly reduced due to the dehydration condensation of OH on the saponite surface making the O content reduced, while the Si content increased due to the reaction of KH570 with OH on the SAP surface and introducing the branched chains of KH570 onto the saponite surface, which indicating that PS was successfully grafted onto the saponite surface 31 . Figure 6C showed the C1s high‐resolution spectrum of SAP, from which can be seen that the C1s peaks is divided into C‐C (284.8 eV), C‐O‐C (286.0 eV), and C‐O=C (288.5 eV), where the binding energy at 286.0 eV is mainly attributed to the binding of OH to carbon atoms on the SAP surface, which is favorable to initiate the polymerization of SAP with St. By comparing Figure 6C,D, it can be seen that the contents of C‐O=C, C‐C, and C‐O‐C in SAP‐g‐PS are higher than those in unmodified SAP.…”

Layered Double Hydroxides: Recent Progress and Promising Perspectives Toward Biomedical Applications

“…To improve the compatibility between LDHs and PLA, many studies have used chemical modification methods to modify LDHs. [272][273][274] However, chemical modification may bring about issues with biocompatibility, which limits the biomedical applications of composites. Interestingly, a recent study has used a combination of electrospinning and electrospray techniques to prepare a PLA/LDH composite membrane.…”

The Effects of Nucleating Agents and Processing on the Crystallization and Mechanical Properties of Polylactic Acid: A Review

“…The morphology of the PLA–talc crystals exhibits an epitaxial growth into a lamellar structure. Other mineral-based materials, such as mica [ 85 ], kaolinite [ 86 , 87 ], layered double hydroxides (LDHs) [ 88 , 89 , 90 , 91 ], and vermiculite (VMT) [ 92 , 93 , 94 ], can also serve as nucleating agents for PLA and affect the nucleation density and crystallization rates.…”