Graft Polymerization Research Articles

Breaking of Supercooling of Water Using Silver Iodide Immobilized on Fiber Prepared by Radiation-induced Graft Polymerization

Breaking of Supercooling of Water Using Silver Iodide Immobilized on Fiber Prepared by Radiation-induced Graft Polymerization

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Aluminum nanoparticles have significant potential applications in various fields due to their unique LSPR. A facile and efficient free‐radical polymerization induced grafting‐to (FRPIGt) method for grafting polymer chains onto Al NPs by Al—C bonds has been reported. This method paves a new path for the preparation of a wide range of polymer‐functionalized Al NPs and their polymer composites to be utilized in various fields. More details are discussed in the article by Liu et al. on pages 3193—3200. image

Advancing Adult-Acquired Flatfoot Deformity Treatment: Enhanced Biomechanical Support Through Graphene Oxide-Integrated Bioengineered Grafts Tested In Silico

Adult-Acquired Flatfoot Deformity (AAFD) is a progressive orthopedic condition causing the collapse of the foot’s medial longitudinal arch, often linked with injuries to the plantar arch’s passive stabilizers, such as the spring ligament (SL) and plantar fascia. Conventional treatment typically involves replacing the SL with synthetic material grafts, which, while providing mechanical support, lack the biological compatibility of native ligaments. In response to this shortcoming, our study developed an electrospun, twisted polymeric graft made of polycaprolactone (PCL) and type B gelatin (GT), enhanced with graphene oxide (GO), a two-dimensional nanomaterial, to bolster biomechanical attributes. The addition of GO aimed to match the native ligamentous tissue’s mechanical strength, with the PCL-GT-GO 2.0% blend demonstrating an optimal Young’s modulus of 240.75 MPa. Furthermore, the graft showcased excellent biocompatibility, evidenced by non-hemolytic reactions, suitable wettability and favorable platelet aggregation—essential features for promoting cell adhesion and proliferation. An MTT assay revealed cell viability exceeding 80% after 48 h of exposure, highlighting the potential of the graft as a regenerative scaffold for affected ligaments. Computational modeling of the human foot across various AAFD stages assessed the graft’s in situ performance, with the PCL-GT-OG 2.0% graft efficiently preventing plantar arch collapse and offering hindfoot pronator support. Our study, based on in silico simulations, suggests that this bioengineered graft holds significant promise as an alternative treatment in AAFD surgery, marking a leap forward in the integration of advanced materials science for enhanced patient care.

A Monte Carlo study on a 3-dimensional comb polymer translocation through a nanopore driven by an electric field

Abstract A lattice Monte Carlo simulation study of the translocation of comb polymers through a nanopore subjected to an electric field is presented. The translocation dynamics was extensively studied in terms of the applied electric field strength, the pore size, and the comb polymer topology. The variations of the most probable translocation time $\tau_p$ and the mean translocation time \mt\ as a function of the applied electric field strength show distinct features, the latter exhibiting a nonmonotonic dependence on the electric field. We were able to show the existence of a critical field strength $\delta \epsilon_c$ defined by the narrowest distribution of the translocation time, which is closely related to the size of the nanopore. In addition, we have found that the critical field strength also defines a transition point between two regimes of translocation: a smooth translocation for a field strength below $\delta \epsilon_c$ and a chaotic translocation for a field strength above $\delta \epsilon_c$. Moreover, for the smallest pore size ($r_p = 1$), monomers can only cross the nanopore in a single file, while for larger pores different modes of polymer translocation are identified. Finally, the dependence of the mean translocation time on the backbone length is governed by a power law relationship $\left < \tau \right > \sim {N_B}^{\alpha}$, where the scaling exponent $\alpha$ is found to be in the range of 1.3--1.7 for the set of side chain lengths and nanopore sizes investigated. As for the side chain length $N_S$, the mean translocation time is found to follow a linear dependence $\left < \tau \right > \sim {N_S}$.

Effects of spherical, disk-like and lamellar nanocomposite particles on cold flow behaviors of waxy crude oil

Wax precipitation and deposition are challenging hurdles in pipeline transportation of waxy crude oil. This study focuses on transforming SiO2, Laponite, and montmorillonite particles into hydrophobic particles through polymer grafting. Chemical structure analysis and grafting ratio calculation were performed. Through thermogravimetric analyzer (TGA) test, Laponite showed the highest grafting ratio. The effects of adding nanocomposites, TDA-2024-22, and commercial pour point depressants on the rheological behavior and wax crystallization behavior of African crude oil were compared. Addition of the nanocomposite PDA-22@SiO2 to crude oil, reduced the viscosity by 85.6% at 20 °C and the thixotropy by 60.2%. Wax crystal size decreased in the order of PDA-22@SiO2, PDA-22@Laponite, KS-10, TDA2024-22, and PDA-22@MMT. The pour point decreased by 6 °C with PDA-22@ SiO2 particles but only 3 °C with Laponite and montmorillonite composites. Spherical nanocomposites are promising flow improvers for waxy crude oil.

PE/PP fibrous adsorbents with bifunctional groups of tertiary amine and phosphate prepared by electron beam induced co-grafting for heavy metal adsorption of both cationic and anionic forms in acidic conditions.

A novel fabric adsorbent having bifunctional groups of tertiary amine and phosphate was prepared by co-graft polymerization of 2-diethylaminoethyl methacrylate (NMA) and 2-hydroxyethyl methacrylate phosphate (PMA) onto a polyethylene/polypropylene nonwoven fabric (PE/PP NF) under low-energy electron beam acceleration. The process involved pre-irradiating the fabric and immersing it in the comonomer solution for grafting. The kinetics of radiation-induced graft polymerization at a total dose of 100 kGy was investigated. For pre-irradiation at 100 kGy, the optimum condition offering highest degree of grafting was at 12 wt% of NMA, 8 wt% of PMA and 4 h of reaction time. The adsorption of anions using hydrogen chromate (HCrO4−) or Cr(VI) and cations using lead (Pb(II)), cadmium (Cd(II)) and copper (Cu(II)) in aqueous solution was carried out. The results demonstrated that the bifunctional adsorbent was able to adsorb both heavy metal anionic and cationic ions from water. The co-grafted adsorbents with tertiary amine and phosphate were able to adsorb 85% Cr(VI) anion and 29% Pb(II) cations from mixed Cr(VI) and Pb(II) solution at pH 3.0 and 71% Pb(II), 13% Cd(II) and 31 % Cu(II) from mixed Pb(II), Cd(II) and Cu(II) solution at pH 5.0. The unique achievement of this study is its hypothesis that a bifunctional adsorbent can be prepared from radiation-induced graft polymerization of two different monomers onto NF, along with proof that the prepared bifunctional adsorbent can actually absorb both cationic or anionic heavy metals forms. Additionally, the adsorbent's preparation offers a rapid and straightforward one-step grafting technique. Therefore, the new bifunctional adsorbents can remove heavy metal ions in aqueous solution, either in the cation or anion form, thus offering highly promising applications in industrial wastewater treatment.

Gamma radiation induced optimized synthesis of amine functionalised poly-glycidyl methacrylate grafted poly-propylene non-woven fabric and its adsorption behaviour towards aqueous Pb(II)

Comprehensive optimization of the functionalization of polypropylene (PP) non-woven fabric through gamma irradiation-induced graft polymerization of glycidyl methacrylate (GMA), results in a material having high grafting yield. The technique, utilizing a mutual irradiation method, produced poly-GMA (PGMA) grafted PP fabric with a remarkable grafting yield of 125 % in a 1:1 acetone–water mixture, subjected to 25 kGy of total dose at a dose rate of 5 kGyh−1. The enhancement of the amination process utilizing PGMA-grafted PP was investigated with polyamines. Under the optimized conditions, the diethylene triamine (DETA) functionalized variant was identified as an effective adsorbent for aqueous Pb2+ ions. The optimized adsorbent exhibited a high saturation capacity of approximately 230 mgg−1 for Pb2+ ions, demonstrating rapid kinetics at near-neutral pH and 25 °C. This low cost innovative material holds significant promise for effective lead removal from drinking water and industrial wastewater, offering a sustainable economical solution for environmental remediation.

Ethylene Polymerization Activity vs Grafting Affinity Trade-off Revealed by Importance Learning Analysis of In Silico Phillips Catalyst

Ethylene Polymerization Activity vs Grafting Affinity Trade-off Revealed by Importance Learning Analysis of <i>In Silico</i> Phillips Catalyst

Preclinical assessment of transcatheter-delivered expandable endoluminal polymeric graft fabricated by electrospinning of microfiber

Abstract Background Matrix fabricated from electrospinning of micro fibre of polyester is porous and permeable to blood, facilitates cell infiltration and late resorption of the biodegradable material. This biomaterial opens an avenue of research in recreating a novel and favourable endoluminal lining in diseased vessel. Previous preclinical work has shown that implants in aorta of rodents generate layers of endoluminal elastin. In humans, one of the most impervious arteries to atherosclerosis is the intra-thoracic artery; therefore, an attempt to induce similar structures with an implantable device was made. Methods For this study, novel tissue-engineered vascular grafts (T-TEVGs) were used in a preclinical rabbit iliac artery model. It was made of resorbable polyester biomaterial processed into fibrous tubular conduits. These T-TEVGs were implanted percutaneously. In total, twelve T-TEVGs in iliac arteries of nine rabbits were implanted. Follow-up were conducted on five rabbits with eight T-TEVGs at three months, two rabbits with two T-TEVGs at six months, and two rabbits with two T-TEVGs at twelve months. At follow-up, percutaneous optical coherence tomography (OCT) was performed, and OCT-derived luminal vessel wall dimensions and fractional flow reserve (OFR) derived from OCT were assessed. Results The overall pooled analysis at different timepoints on follow-up, documented an average MLA of 1.74±0.48mm2, average of proximal and distal reference area of 4.55±0.99 mm2, average area stenosis of 61±12%, and mean OFR value of 0.96±0.03 (OFR ranging from 0.89 to 0.99). There was a moderate positive correlation between minimum lumen area and OFR (r=0.590, p&amp;lt; 0.01). There was a strong negative correlation between percentage area stenosis and OFR (r= - 0.846, p&amp;lt; 0.01). At no timepoint in follow-up and in every vessel analysed, OFR value was lower than 0.89, suggesting that none of these vessels exhibited flow-limiting narrowing. Our study has a few limitations. 1) The preclinical model is a non-atherosclerotic rabbit; 2) There was no barotrauma prior to the implantation of the device; 3) Limited sample size, short and medium follow-up duration, and pooling of assessment at different timepoints. Conclusion The current study shows the durability and favourable hemodynamics of this bioresorbable fibrillated scaffold at short and medium term follow-up, supporting the potential utility of T-TEVEGs for peripheral human artery revascularisation. Long-term follow-ups are mandatory to confirm the durability of these results. Histopathology of this preclinical model should confirm the endoluminal elastin as previously documented in rodents (rats) and will be presented at the time of the congress.

Exponential growth rate of lattice comb polymers

Abstract We investigate a lattice model of comb polymers and derive bounds on the exponential growth rate of the number of embeddings of&amp;#xD;the comb. A comb is composed of a backbone that is a self-avoiding walk and a set of $t$ teeth, also modelled as mutually and self-avoiding walks, attached to the backbone at vertices or nodes of degree 3. Each tooth of the comb has $m_a$ edges and there are $m_b$ edges in the backbone between adjacent degree 3 vertices and between the first and last nodes of degree 3 and the end vertices of degree 1 of the backbone. We are interested in the exponential growth rate as $t \to \infty$ with $m_a$ and $m_b$ fixed. We prove upper bounds on this growth rate and show that for small values of $m_a$ the growth rate is strictly less than that of self-avoiding walks.

Shape-Memory Property Acting as a Switch to Change the Surface Property of the Film

Shape-memory polyester films having functional groups were prepared and further grafted onto poly(N-isopropylacrylamide) (PNIPAAm) via atom-transfer radical polymerization. The grafting point of PNIPAAm was controlled by changing the composition of good and poor solvents. In the case of graft polymerization using only good solvents, the film swells, and polymerization proceeds not only from the surface but also from the internal polymerization initiation points. By increasing the proportion of poor solvents, PNIPAAm was grafted onto the surface of the film without swelling. The samples grafted to the interior regions of the film exhibited a decrease in the shape-memory recovery rate and recovery speed, whereas the samples grafted only to the surface of the film exhibited high shape-memory properties. Furthermore, contact-angle measurements revealed that the surface-grafted polymer exhibited changes in surface properties in response to film deformation. Because the deformation of the film is a large change, on the order of several millimeters, the deformation of the manually stretched film was shown to control molecular-level changes on the surface.

Effect of radiation-induced graft polymerization onto pineapple nonwoven fabric reinforced polymer composite

Natural fiber-reinforced polymer composites are gaining attention for their environmental benefits, such as biodegradability and reduced carbon footprint, as well as the potential of the natural fibers to replace or partially substitute synthetic fibers in various applications. However, challenges, such as poor interfacial adhesion and moisture absorption, limit the effectiveness of natural fibers, such as pineapple nonwoven fabric (PNWF) as reinforcement materials in polymer composites. To address these challenges, this study aims to enhance the properties of PNWF through glycidyl methacrylate grafting via radiation-induced graft polymerization. A 22 factorial design was employed to assess the effects of absorbed dosage and monomer concentration on the properties of the grafted PNWF. Infrared spectroscopy and electron microscopy analyses confirmed successful grafting. The grafted PNWF exhibited improved thermal stability and mechanical properties. The resulting composites showed significant enhancements in tensile and flexural strength, specifically, with tensile strength increase ranging from 23.32 to 34.49 MPa and flexural strength from 39.14 to 54.59 MPa. Additionally, the tensile modulus ranged from 0.77 to 1.29 GPa, while the flexural modulus varied from 1.17 to 2.06 GPa. These findings highlight the potential of PNWF grafted with polyglycidyl methacrylate (PNWF-g-PGMA) as an effective reinforcement material for various applications.

Influence of the rigidity of the backbone and arms on the dynamical and conformational properties of the comb polymer in shear flow.

The dynamical and conformational properties of the comb polymer with various rigidities of the backbone and arms in steady shear flow are studied by using a hybrid mesoscale simulation approach that combines multiparticle collision dynamics with standard molecular dynamics. First, during the process of the comb polymer undergoing periodic tumbling motion, we find that the rigidity of the arms always promotes the tumbling motion of the comb polymer, but the rigidity of the backbone shifts from hindering to promoting it with increasing the rigidity of the arms. In addition, the comb polymer transitions from vorticity tumbling to gradient tumbling with the increase in shear rate. Second, the range of variation of the end-to-end distance of the backbone and the average end-to-end distance of the arms increases with the increase in the rigidity of the arms and backbone, respectively, and the range of both changes grows with the increase in shear rate. Furthermore, as the rigidity increases, the moldability of the comb polymer decreases and the orientation angle of the comb polymer increases.

Rewritable Surface‐Grafted Polymer Brushes with Dynamic Covalent Linkages

AbstractSurface grafting of polymer brushes drastically modifies surface properties, including wettability, compatibility, responsiveness, etc. A broad variety of functionalities can be introduced to the surface via different types of polymers. Bringing together properties of two or more types of polymer brushes to one surface opens up even more possibilities in brush‐modified materials. However, while it is generally feasible to introduce several chemical compositions along the brushes via copolymerization, it is challenging to vary the types of polymer brushes along a surface. Although previous studies have demonstrated binary brushes via orthogonal polymerization techniques or partial deactivation/regrafting, they commonly limit the number of polymer types to two. Here, we propose a strategy to introduce dynamic covalent diketoenamine linkages at the root of polymer brushes. The grafting density could be precisely tuned during surface functionalization. The surface‐anchored polymer brushes were cleaved by the addition of small molecule amines. New polymer brushes can be regrafted from the surface following refunctionalization of exposed sites. The maneuverability allows tuning of the types and densities of the polymer brushes, pointing the way to the preparation of a new generation of well‐defined brush‐modified materials with mixed grafts, with potential applications in the design of smart materials and surfaces.

Synthesis and Characterization of cellulose-derived superabsorbent hydrogel and its applications in the treatment of wastewater containing heavy metal ions

A cellulose xanthate (CX) based polymer hydrogel has been synthesized using free radical graft polymerization technique. Two monomers Acrylic Acid (AA) and Acrylonitrile (AN) were reacted with cellulose xanthate to synthesize the desired hydrogel CX-g-poly(AA-co-AN). The synthesized hydrogel has been characterized by various techniques viz. Thermo-gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), UV-visible spectroscopy (UV), Field emission scanning electron microscope (FESEM) and Point zero charge (PZC). This hydrogel has been employed for the removal of toxic metal ions from wastewater. The maximum percentage removal has been found to be 97.5 (±4.87)% for Cu2+ ions and 96.1 (±4.80)% for Co2+ ions under optimum pH 6. The calculated adsorption capacities have been found to be 330.03 (±35.3) mg/g for Cu2+ ions and 325.73 (±22.4) mg/g for Co2+ ions using the Langmuir Adsorption isotherm model. The thermodynamic parameters depicted that the process was endothermic, and spontaneous. The adsorption kinetics data shows excellent fit with pseudo-second-order kinetic model. The synthesized hydrogel exhibits a high swelling ratio of 846.85 (±42.36) g/g and retention ratio of 50.12 (±2.50) % in distilled water. Also, the synthesized hydrogel showed good reusability, exhibiting percentage removal 83.2% for Cu2+ ions and 81.3% for Co2+ ions in the fifth cycle.

Synthesis and characterization of guar gum xanthate derivative super adsorbent hydrogel for the capturing of heavy metal ions from wastewater

The Guar Gum Xanthate based hydrogel GGmX-g-poly(AA-co-HEMA) has been successfully synthesized by using the graft copolymerization of two monomers, acrylic acid (AA) and 2-hydroxyethyl methacrylate (HEMA) hydrogel. The synthesis follows the free-radical graft polymerization method. UV-visible spectroscopy (UV), Thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), Point zero charge (PZC), and field emission scanning electron microscopy (FESEM) were employed for the characterization of the synthesized hydrogel. This hydrogel has shown a high swelling ratio of 430.2 g/g and retention of 75.82% in distilled water which is a notable result. By using GGmX-g-poly(AA-co-HEMA) hydrogel, the maximum percentage of heavy metal ions removal from wastewater was found to be 98.5(±1.5)% and 97.1(±1.5) at optimum pH 6 and 6.5 for Cu2+ and Ni2+ solutions respectively. The Langmuir adsorption isotherm fits best for the adsorption data indicating a monolayer adsorption with maximum adsorption capacity of 423.72 (±26.1) mg/g and 404.85 (±31.4) mg/g for Cu2+ and Ni2+ ions respectively. The pseudo-second-order kinetic model provides the most accurate depiction of adsorption kinetics with rate constant 9.1 × 10−4 (±1.37×10−4)g/(mg.min) for Cu2+ and 8.3 × 10−4 (±1.24×10−4)g/(mg.min) for Ni2+ ions, respectively. The negative ΔG value (-4.75 kJ/mol for Cu2+ and −3.26 kJ/mol for Ni2+ ions) and positive value of ΔH (57.55 (±5.41) kJ/mol for Cu2+ and 40.60(±5.37) kJ/mol for Ni2+ ions) suggested the process to be spontaneous, endothermic, and feasible. It has been found that the hydrogel has excellent regenerative capacity with the % adsorption has been found to be 84.8% for Cu2+ and 82.4% for Ni2+ ions for the fifth cycle.

Sodium alginate-g-polyacrylamide hydrogel for water retention and plant growth promotion in water-deficient soils

Natural polymer-based hydrogels are preferred as soil water retention agents due to their inherent biocompatibility and biodegradability. Generally, these natural polymers are chemically modified by graft polymerization of vinyl monomers to improve their water absorption and retention properties. Among the polysaccharides used to prepare natural hydrogels, those based on sodium alginate (Alg) stand out for their high-water absorption and retention capacity, as well as for their ability to promote plant growth. The main objective of this study was to develop a biodegradable alginate-based hydrogel as a water retainer to promote plant growth under water deficit conditions. The synthesis was achieved by grafting poly(acrylamide) (PAM) onto Alg backbone, using bisacrylamide as chemical crosslinker and different ratios of alginate:acrylamide (Ac). In addition, Eucalyptus nitens seedlings were used as a model plant to evaluate the effect of alginate-g-polyacrylamide (Alg:PAM) hydrogel application to the growing medium on plant survival, growth, and physiological responses under both well-watered and water-deficient soil conditions. The maximum degree of swelling (65 g/g) was obtained for the hydrogel prepared. The pseudo-second order model described the water uptake kinetics of the hydrogel. The degradability of Alg:PAM hydrogel reached up to 85 % in 5 weeks in soil and occurs by breaking the glycosidic bonds of the alginate. The E. nitens seedlings cultivated with different doses of Alg:PAM hydrogel (4:1 Alg:Ac) showed higher values of height and root diameter relative growth, survival and photosynthetic responses in comparison to non-treated plants. The results indicate that Alg:PAM hydrogel (4:1 Alg:Ac) has promising applications in forestry as a water retention and seedling growth promoter under water deficient conditions.

From Fully Stretched to Collapsed Chains: Bottlebrush Polymer Grafted Particles

From Fully Stretched to Collapsed Chains: Bottlebrush Polymer Grafted Particles

Compatibilizing and toughening of the styrene and acrylonitrile copolymer and core‐shell impact modifier obtained by agglomerate technologies

AbstractParticle size distribution and the compatibility of core‐shell impact modifiers play a crucial role in determining the mechanical properties of the resin. This study presents the synthesis of a core‐shell impact modifier, a copolymer of polybutadiene grafted with styrene and acrylonitrile (PBL‐g‐SAN), using emulsion polymerization to enhance the mechanical properties of SAN resin. Polymer agglomeration technologies were employed to increase the particle size of polybutadiene latex, resulting in particles approximately 300 nm in diameter. Moreover, the effects of core‐shell modifiers with different constitutions on the mechanical properties of ABS resin were investigated. By optimizing the grafting polymerization process, improvements in impact strength of ABS resin were observed. When the St/AN ratio of the core‐shell modifier is 75/25, with a core‐shell ratio of 60/40 and MMA content at 2.5%, the impact strength of ABS resin reaches its peak while maintaining high tensile strength. The incorporation of methyl methacrylate improved the dispersion of core‐shell modifiers in SAN resin. Compared to commercial ABS resins with the same SAN and rubber content, the modified resin demonstrated a nearly 20% improvement in impact performance, and significant reductions in both production time and costs due to the polymer agglomeration method.Highlights The 300 nm polybutadiene latex was synthesized by polymer agglomeration technology. The relationship between the composition of these core‐shell modifiers and the mechanical properties of ABS resin was explored. The ABS resin with impact strength exceeding 20% of commercial material is prepared.

Easy Direct Functionalization of 2D MoS2 Applied in Covalent Hybrids with PANI as Dual Blend Supercapacitive Materials

AbstractThe pressing demand for more sustainable energy provision and the ongoing transition toward renewable resources underline the critical need for effective energy storage solutions. To address this challenge, scientists persistently explore new compounds and hybrids and, in such a dynamic research field, 2D materials, particularly transition metal di‐chalcogenides (TMDCs), show great potential for electrochemical energy storage uses. Simultaneously, also conductive polymers (CPs) are interesting and versatile supercapacitor materials, especially polyaniline (PANI), which is extensively studied for this purpose. In this work, a powerful method to combine TMDCs and PANI into covalently grafted hybrids starting from aniline functionalized few‐layers 1T‐MoS2, attained by a facile direct arylation with iodoaniline, is presented. The hybrids provide circa 70 F g−1 specific capacitance in a pseudo device setup, coupled with a robust capacitance retention of well over 80% for up to 5000 cycles. These findings demonstrate the potential of similar covalent composites to work as active components for novel, innovative energy storage technologies. At the same time, the successful synthesis marks the efficacy of direct covalent grafting of conductive polymer on the surface of 2D TMDCs for stable functional materials.