Graft Copolymers Research Articles

Starch Hydrogels for Slow and Controlled-Release Fertilizers: A Review

Fertilizers are widely used to increase agricultural productivity and ensure food security. However, their excessive use negatively impacts the environment, as a large portion is lost through leaching, degradation, and evaporation. Starch-based hydrogels (SHs) offer a promising alternative to mitigate these environmental effects by enabling the controlled release of nutrients. SHs are biodegradable, non-toxic, and biocompatible, making them attractive for agricultural applications such as soil remediation and fertilizer delivery. These materials consist of crosslinked, three-dimensional networks with high water absorption capacity. Their effectiveness in nutrient delivery depends on the synthesis method, nutrient source, and environmental conditions. While the literature on SHs is growing, most studies focus on laboratory-scale production, which limits their broader application in agriculture. This review aims to consolidate current knowledge on SHs and identify research gaps to guide the development of more efficient and environmentally friendly SH-based fertilizers. It provides an overview of SH formation methods, including graft copolymerization, chemical crosslinking, and physical interactions. Additionally, the review highlights SH applications in controlled fertilizer release, discussing encapsulation capacity, large-scale production techniques, and nutrient delivery in aqueous media, soils, seeds, and plants.

Photo-Switching from Enzymatic Reaction to DNA Self-Assembly Enabled by a Caged Cationic Copolymer.

Enzymatic reactions that act on DNA and DNA self-assembly reactions have been harnessed to create sophisticated dynamic DNA nanodevices. Methods for temporally and spatially controlling these reactions will enable creation of more advanced DNA nanodevices. We previously reported that cationic graft copolymers activate DNA self-assembly reactions including DNA hybridization and strand displacement reactions while inhibiting reactions catalyzed by enzymes that act on DNA. In this study, we prepared a photoactivatable graft copolymer as a tool to spatiotemporally switch between enzymatic and self-assembly reactions upon photoirradiation. The graft copolymer caged at their amino groups with photocleavable 6-nitroveratryloxycarbonyl moieties did not inhibit polymerase reactions and did not activate toehold-mediated strand displacement reactions. After UV irradiation to uncage the amino groups of the copolymer, polymerase activity was inhibited and toehold-mediated strand displacement was activated. Thus, remote switching from polymerization to toehold-mediated strand displacement was performed by photoirradiation.

Enhancing the compatibility and performance of poly (lactic acid) and thermoplastic polyolefin elastomer blends through a dual compatibilization strategy.

Enhancing the compatibility and performance of poly (lactic acid) and thermoplastic polyolefin elastomer blends through a dual compatibilization strategy.

Thermal and physicochemical dissimilarities of biological poly-3-hydroxyalkanoates following graft copolymerization with acrylamide under ultrasonication.

Thermal and physicochemical dissimilarities of biological poly-3-hydroxyalkanoates following graft copolymerization with acrylamide under ultrasonication.

Enhancement on durability of cohesive soil by solidifying with modified guar gum.

Enhancement on durability of cohesive soil by solidifying with modified guar gum.

Adsorption of heavy metals from water using teak-based carbon material through graft copolymerization

Adsorption of heavy metals from water using teak-based carbon material through graft copolymerization

Targeting JAK/STAT3 in glioblastoma cells using an alginate-PNIPAm molecularly imprinted hydrogel for the sustained release of ruxolitinib.

Targeting JAK/STAT3 in glioblastoma cells using an alginate-PNIPAm molecularly imprinted hydrogel for the sustained release of ruxolitinib.

Graft copolymerization of HEMA on LLDPE films activated by low-energy electrons

Graft copolymerization of HEMA on LLDPE films activated by low-energy electrons

Reaction mechanism of graft copolymerization in bulk-polymerized ABS resins and its effect on mechanical and combustion properties

Reaction mechanism of graft copolymerization in bulk-polymerized ABS resins and its effect on mechanical and combustion properties

Incorporation of biochar and semi-interpenetrating biopolymer to synthesize new slow release fertilizers and their impact on soil moisture and nutrients availability

Chemical fertilizers (CFs) are indispensable nutrients source for plants replenishing them with essential nutrients. However, their over-utilization imposed destructive consequences of excessive loss of major nutrients resulting in low nutrient use efficiency and further environmental concerns. Therefore, to counter excessive application of CFs and to regulate sustainable agriculture, a novel biochar (BC)-based slow-release fertilizer (SRF) was developed by incorporating mica (MI) and semi-interpenetrating chitosan polymer (Semi-IPN) via graft co-polymerization. Fabricated SRFs were characterized and their nutrient release dynamics as well as soil water holding (WH) and water retention (WR) capacity were investigated. The results revealed that BC-based SRFs, particularly BC-SRF and BCMI-SRF, enhanced soil WH capacity by 40.61% and 47.80%, respectively, whereas the highest soil WR capacity was recorded as 32.55% and 35.52% respectively, after 30 days. The nutrients (NH4+-N, P, K) release ratio of CF and MI was recorded in the range of 85–100%, however BC and MI incorporated SRFs showed splendid slow release nutrients dynamics and release 75.53% of NH4+-N, 65.66% of P and 71.83% of K in a 30 days incubation experiment. Nutrient release kinetics exhibited diffusion and mass transport as the major nutrient release mechanisms, which was confirmed by the best fitted parabolic diffusion and first order kinetics models. Hence, current study inclusively demonstrated new routes for synthesis of innovative and eco-friendly SRFs with substantial slow-release performance to overcome excessive nutrient loss by application of CF.

Graft Copolymerization of Glycidyl Methacrylate/ Acrylamide Monomer Mixture onto Polyethylene Terephthalate Fibers; Characterization and Investigation of Some Properties

Polymers are highly important materials that are widely used in every aspect of our lives. Through grafting, polymers can be modified with desired monomers to acquire specific properties. Polyethylene terephthalate (PET) fibers possess many favorable characteristics such as cheap raw materials, low production costs, and high resistance to environmental effects. However, they also have disadvantages, such as limited water absorption capacity and dyeability due to their hydrophobic nature. This study aims to improve these negative aspects of PET using the graft copolymerization method. In the study, GMA (glycidyl methacrylate) and AAm (acrylamide) monomers containing different functional groups were grafted onto PET fibers using benzoyl peroxide (BPO) as the initiator. Additionally, lipase enzyme was immobilized on the grafted PET fibers, and the use of this immobilized enzyme in the hydrolysis of various types of oils was investigated. Ungrafted and grafted PET fibers were characterized using Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), and Fourier Transform Infrared Spectroscopy (FTIR) to investigate the effects of various parameters on the grafting process. The water retention and dyeability properties of the grafted PET fibers were also demonstrated.

Polymer Chain Modification via HAT Chemistry and Its Application in Graft Copolymer Synthesis.

Hydrogen atom transfer (HAT) chemistry has emerged as a powerful tool for selective molecular functionalization, with significant applications in the pharmaceutical and agricultural industries. More recently, HAT has been explored in polymer chemistry as a versatile strategy for introducing targeted functional groups onto polymer chains, enabling precise control over properties such as solubility and mechanical strength. This study investigates the use of HAT to synthesize reversible addition-fragmentation chain transfer (RAFT) agents (or chain transfer agents, CTAs) by modifying various substrates, including toluene, ethyl acetate, and dioxane, in the presence of bis(dodecylsulfanylthiocarbonyl) disulfide or bis(3,5-dimethyl-1H-pyrazol-1-ylthiocarbonyl) disulfide. The resulting CTAs were evaluated in both thermal and photoinduced electron transfer (PET)-RAFT polymerization for controlled polymerization of various monomers. This approach was then extended to functionalize polycaprolactone (PCL) and polyvinyl acetate (PVAc), enabling the synthesis of graft copolymers with various vinyl monomers. To promote HAT, a range of photocatalysts, including iron(III) chloride (FeCl3), were investigated, offering advantages over conventional thermal HAT systems. Photocatalysis enables mild and efficient radical generation under light irradiation, providing a cost-effective and environmentally friendly alternative to expensive or toxic metal catalysts.

Surface Modification of Polyimide Membrane via Radiation Induced Graft Copolymerization of Methyl Methacrylate: Effects of Monomer Concentration and Radiation Dose

Surface Modification of Polyimide Membrane via Radiation Induced Graft Copolymerization of Methyl Methacrylate: Effects of Monomer Concentration and Radiation Dose

Controlled chain-growth polymerization via propargyl/allenyl palladium intermediates

In contrast to allyl palladium complexes, propargylic/allenylic palladium species display complex reactivities that limit their implementation in polymer chemistry, especially for chain-growth polymerizations. Here we report an example of controlled chain-growth polymerization via propargyl/allenyl palladium intermediates. Vinylidenecyclopropane 1,1-dicarboxylate (VDCP), a unique allenylic electrophile, selectively reacts via the σ-allenyl palladium complex rather than the more common π-propargyl pathway, thereby unlocking a chain-growth process. Based on this concept, precise synthesis of alkyne-backbone polymers is realized, featuring fast rate, high molecular weight, narrow dispersity, high chemoselectivity, and excellent end-group fidelity. We demonstrate preparation of unsaturated macromolecules with advanced sequences and architectures using this method, including block, gradient, and graft copolymers.

Incorporating Ginger Extract as a Bioactive Additive Into Eco‐Friendly Fertilizer Coatings Based on Natural Rubber‐Grafted‐Rice Starch: A Performance Evaluation

ABSTRACTA polymeric coating was developed to minimize fertilizer loss and improve antifungal efficacy against Fusarium sp. by combining natural rubber‐grafted rice starch (NR‐g‐ST) with methanolic ginger extract (GE) for coating granular urea fertilizer. The coating was synthesized via in situ graft copolymerization, employing potassium persulfate as an initiator within an emulsion system. Fourier transform infrared (FT‐IR) spectroscopy confirmed successful grafting and molecular interactions between the hydroxyl groups of starch with both GE and natural rubber (NR). The NR:ST ratio was maintained at 70:30 wt%, while GE content was varied from 0 to 9 wt% relative to the polymer matrix. The coatings were characterized using thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), and water contact angle (WCA) measurements. Increasing GE content enhanced the mechanical properties, storage modulus, and hydrophobicity while reducing biodegradability. The coating demonstrated antifungal efficacy through the inhibition of Fusarium sp. mycelial growth, suggesting its potential as a multifunctional agricultural solution.

Graft copolymerization synthesis of chitosan-polyferric sulfate composite coagulant to improve biogas slurry treatment toward effective irrigation.

Graft copolymerization synthesis of chitosan-polyferric sulfate composite coagulant to improve biogas slurry treatment toward effective irrigation.

Exploring the biodegradation of polysaccharide derivatives in controlled marine conditions: Comparison of paramylon acetate, propionate, and graft copolymers with PLA and PCL

Exploring the biodegradation of polysaccharide derivatives in controlled marine conditions: Comparison of paramylon acetate, propionate, and graft copolymers with PLA and PCL

Crosslinking-induced compatibility and toughness enhancement in poly(lactic acid)/poly(3-hydroxybutyrate-co-4-hydroxybutyrate) blends with epoxidized soybean oil.

Crosslinking-induced compatibility and toughness enhancement in poly(lactic acid)/poly(3-hydroxybutyrate-co-4-hydroxybutyrate) blends with epoxidized soybean oil.

Controlled release of doxorubicin from bio-resolvable drug-eluting bead of GelMA-SPMA graft copolymer for embolotherapy of liver cancer

Controlled release of doxorubicin from bio-resolvable drug-eluting bead of GelMA-SPMA graft copolymer for embolotherapy of liver cancer

Preparation of graft copolymers from Vietnam deproteinized natural rubber with acrylonitrile using tetraethylenepentamine and tert-butyl hydroperoxide radical initiators

Natural rubber is an unsaturated natural elastomer with many superior properties such as high strength, outstanding resilience, and high elongation at break. However, it lacks in some properties due to the unsaturation of carbon-carbon double bonds in the natural rubber backbone causes easy degradation and poor thermal stability. Many techniques have been made use of improving its thermo-mechanical properties. In this study, the graft copolymerization of acrylonitrile onto deproteinization natural rubber was investigated to increase the thermal and mechanical properties of natural rubber. This process was performed successfully in latex using tetraethylenepentamine and tert-butyl hydroperoxide as radical initiators at 30 °C. The effects of acrylonitrile concentration on the conversion and grafting efficiency of the graft copolymerization were studied. The structural characterization of the obtain graft copolymer was carried out by Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy. The improvement in thermal properties of the obtained products was confirmed by Thermal Gravimetric Analysis/Differential Thermal Gravimetric Analysis, which showed that at the optimal condition for graft copolymerization was at acrylonitrile of 15 wt.% per kg of rubber, where the maximum degradation occurred at 377 °C. The mechanical properties of the products were also studied via tensile testing, where the tensile strength of the graft copolymerization using at AN of 15 wt.% per kg of rubber (1.5±0.5MPa), nearly tripled when compared to virgin deproteinized NR (3.8±0.9MPa).