Circumventing inherent embrittlement, poor heat resistance, and melt elasticity of poly­(lactic acid) (PLA) without compromising its remarkable stiffness and strength has become a particular challenge in polymer science due to increasing demand for green materials in emerging applications of sustainable chemistry and engineering. Achieving this without using any high-cost reagent/additive and/or complex processing technique is another critical aspect for developing industrially viable alternatives to petroleum-based commodity plastics. Here we demonstrate that high-shear mixing of PLA with waste cross-linked polyurethanes and waste cellulose fibers allows for overcoming its inherent embrittlement, poor heat resistance, and melt elasticity without compromising its superior stiffness and strength while suggesting a sustainable way of recycling/reusing industrial wastes as high added-value additives. We therefore achieve to produce stiff, strong, super-tough, and heat-resistant PLA-based green materials, for instance, with an elastic modulus of 4 GPa at 25 °C (∼30% higher than that of pure PLA), a storage modulus of 312 MPa at 90 °C (∼44 times higher than that of pure PLA), a tensile strength of 65 MPa (comparable to that of PLA), and an impact strength (toughness) of 52 kJ/m2 (∼2.3 times higher than that of pure PLA).

The use of chemical pesticides is limited by several public health concerns regarding their toxicity levels and indiscriminate use. Nevertheless, they are still vital components of agricultural industry since no other competitive equivalents to chemical pesticides still exist in terms of efficiency. This study describes the preparation and biological assessment of an insecticide releasing plastic film for agricultural covering purposes. The formulation was prepared by incorporation of deltamethrin loaded, nano-sized halloysite nanotubes into polymeric films. Thermal, morphological, and mechanical properties of films were characterized by Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM) and Universal Testing Machine UTM. Sustained release profiles of the films were evaluated by Thermogravimetric Analysis (TGA). Results reveal that deltamethrin was successfully loaded into halloysite nanotubes and nanotube incorporation enhances the elastic modulus of linear-low density polyethylene (LLDPE) films. In addition, films exhibit controlled release function of the active agent for 32 days. Bioassays of the nanocomposite films with varying deltamethrin doses tested on grasshoppers showed that the LD50 values of the films are 1.85 10 !! g/cm 2 . Insecticidal activities of films were tested in greenhouse on Medicago Sativa plants contaminated with thrips and aphid. Nanocomposites are observed to repel mature aphids and kill young aphids and thrips.

Thermoplastic polyurethanes (TPUs) are designed using a large variety of basic building blocks but are only synthesized in a limited number of solvent systems. Understanding the behavior of the copolymers in a selected solvent system is of particular interest to tune the intricate balance of microphase separation/mixing, which is the key mechanism behind the structure formation in TPUs. Here, we present a computationally efficient approach for selecting TPU building blocks and solvents based on their Flory–Huggins interaction parameters for a precise control over the microphase separation/mixing. We first cluster eight soft segments (PEO, PPO, PTMO, PBA, PCL, PDMS, PIB, or PEB) used frequently in TPUs into three categories according to the strength of their interactions with the binary solvent THF/DMF. We then perform a comprehensive set of dissipative particle dynamics simulations of the TPUs in a range of solvent ratios. This enables us to demonstrate the emergence of the unusual channel-like structures in a narrow range of parameters and to determine the critical interactions operative for obtaining either microphase separated or mixed structures. The findings are supported by thermodynamic arguments. The approach developed here is useful for designing novel TPUs with well-defined conformational characteristics, controlled morphologies, and advanced functional properties.

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Superabsorbent polymers (SAPs) are useful polymers in a wide range of application fields ranging from the hygiene industry to construction and agriculture. As versatility and high water absorption capacity are their important merits, SAPs usually suffer from low water retention capacity (fast release) and weak mechanical properties. To address these drawbacks, a set of new superabsorbent polymer–Halloysite nanotube (HNT) nanocomposites was synthesized via free radical polymerization of acrylamide, 2-acrylamido-2-methylpropane-1-sulfonic acid, and acrylic acid in the presence of vinyltrimethoxysilane (VTMS) as the crosslinker. FTIR and TGA characterizations confirm the polymerization of SAP and successful incorporation of HNTs into the SAP polymer matrix. The effect of the HNT nanofiller amount in the nanocomposite polymer matrix was investigated with swelling–release performance tests, crosslink density calculations, and rheology measurements. It was found that equilibrium swelling ratios are correlated and therefore can be tuned via the crosslink densities of nanocomposites, while water retention capacities are governed by storage moduli. A maximum swelling of 537 g/g was observed when 5 wt % HNT was incorporated, in which the crosslink density is the lowest. Among the SAP nanocomposites prepared, the highest storage modulus was observed when 1 wt % of nanofiller was incorporated, which coincides with the nanocomposite with the longest water retention. The water release duration of SAPs was prolonged up to 27 days with 1% HNT addition in parallel with the achieved maximum storage modulus. Finally, three different incorporation mechanisms of the HNT nanofiller into the SAP nanocomposite structure were proposed and confirmed with rheology measurements. This study provides a rapid synthesis method for SAP nanocomposites with enhanced water retention capacities and explains the relationship between swelling and crosslink density and water retention and mechanical properties of SAP nanocomposites.