Hyperbranched Polymer-based Nanocomposites: Synthesis, Progress, and Applications

Hydrophilic Poly(meth)acrylates by Controlled Radical Branching Polymerization: Hyperbranching and Fragmentation

Topology significantly impacts polymer properties and applications. Hyperbranched polymers (HBPs) synthesized via atom transfer radical polymerization (ATRP) using inimers typically exhibit broad molecular weight distributions and limited control over branching. Alternatively, copolymerization of inibramers (IB), such as α-chloro/bromo acrylates with vinyl monomers, yields HBPs with precise and uniform branching. Herein, we described the synthesis of hydrophilic HB polyacrylates in water by copolymerizing a water-soluble IB, oligo(ethylene oxide) methyl ether 2-bromoacrylate (OEOBA), with various hydrophilic acrylate comonomers. Visible-light-mediated controlled radical branching polymerization (CRBP) with dual catalysis using eosin Y (EY) and copper complexes resulted in HBPs with various molecular weights (M n = 38 000 to 170 000) and degrees of branching (2%-24%). Furthermore, the optimized conditions enabled the successful application of the OEOBA to synthesize linear-hyperbranched block copolymers and hyperbranched polymer protein hybrids (HB-PPH), demonstrating its potential to advance the synthesis of complex macromolecular architecture under environmentally benign conditions. Copolymerization of hydrophilic methacrylate monomer, oligo(ethylene oxide) methyl ether methacrylate (OEOMA500), and inibramer OEOBA was accompanied by fragmentation via β-carbon C-C bond scission and subsequent growth of polymer chains from the fragments. Furthermore, computational studies investigating the fragmentation depending on the IB and comonomer structure supported the experimental observations. This work expands the toolkit of water-soluble inibramers for CRBP and highlights the critical influence of the inibramer structure on reaction outcomes.

Preparation and Application of Amino-Terminated Hyperbranched Magnetic Composites in High-Turbidity Water Treatment

In order to separate the colloidal in high-turbidity water, a kind of magnetic composite (Fe3O4/HBPN) was prepared via the functional assembly of Fe3O4 and an amino-terminal hyperbranched polymer (HBPN). The physical and chemical characteristics of Fe3O4@HBPN were investigated by different means. The Fourier Transform infrared spectroscopy (FTIR) spectra showed that the characteristic absorption peaks positioned at 1110 cm-1, 1468 cm-1, 1570 cm-1 and 1641 cm-1 were ascribed to C-N, H-N-C, N-H and C=O bonds, respectively. The shape and size of Fe3O4/HBPN showed a different and uneven distribution; the particles clumped together and were coated with an oil-like film. Energy-dispersive spectroscopy (EDS) displayed that the main elements of Fe3O4/HBPN were C, N, O, and Fe. The superparamagnetic properties and good magnetic response were revealed by vibrating sample magnetometer (VSM) analysis. The characteristic diffraction peaks of Fe3O4/HBPN were observed at 2θ = 30.01 (220), 35.70 (311), 43.01 (400), 56.82 (511), and 62.32 (440), which indicated that the intrinsic phase of magnetite remained. The zeta potential measurement indicated that the surface charge of Fe3O4/HBPN was positive in the pH range 4-10. The mass loss of Fe3O4/HBPN in thermogravimetric analysis (TGA) proved thermal decomposition. The -C-NH2 or -C-NH perssad of HBPN were linked and loaded with Fe3O4 particles by the N-O bonds. When the Fe3O4/HBPN dosage was 2.5 mg/L, pH = 4-5, the kaolin concentration of 1.0 g/L and the magnetic field of 3800 G were the preferred reaction conditions. In addition, a removal efficiency of at least 86% was reached for the actual water treatment. Fe3O4/HBPN was recycled after the first application and reused five times. The recycling efficiency and removal efficiency both showed no significant difference five times (p > 0.05), and the values were between 84.8% and 86.9%.

A Comprehensive Review on Processing, Development and Applications of Organofunctional Silanes and Silane-Based Hyperbranched Polymers

Since the last decade, hyperbranched polymers (HBPs) have gained wider theoretical interest and practical applications in sensor technology due to their ease of synthesis, highly branched structure but dimensions within nanoscale, a larger number of modified terminal groups and lowering of viscosity in polymer blends even at higher HBP concentrations. Many researchers have reported the synthesis of HBPs using different organic-based core-shell moieties. Interestingly, silanes, as organic-inorganic hybrid modifiers of HBP, are of great interest as they resulted in a tremendous improvement in HBP properties like increasing thermal, mechanical and electrical properties compared to that of organic-only moieties. This review focuses on the research progress in organofunctional silanes, silane-based HBPs and their applications since the last decade. The effect of silane type, its bi-functional nature, its influence on the final HBP structure and the resultant properties are covered in detail. Methods to enhance the HBP properties and challenges that need to be overcome in the near future are also discussed.

Dendritic Polymers in Tissue Engineering: Contributions of PAMAM, PPI PEG and PEI to Injury Restoration and Bioactive Scaffold Evolution

The capability of radially polymerized bio-dendrimers and hyperbranched polymers for medical applications is well established. Perhaps the most important implementations are those that involve interactions with the regenerative mechanisms of cells. In general, they are non-toxic or exhibit very low toxicity. Thus, they allow unhindered and, in many cases, faster cell proliferation, a property that renders them ideal materials for tissue engineering scaffolds. Their resemblance to proteins permits the synthesis of derivatives that mimic collagen and elastin or are capable of biomimetic hydroxy apatite production. Due to their distinctive architecture (core, internal branches, terminal groups), dendritic polymers may play many roles. The internal cavities may host cell differentiation genes and antimicrobial protection drugs. Suitable terminal groups may modify the surface chemistry of cells and modulate the external membrane charge promoting cell adhesion and tissue assembly. They may also induce polymer cross-linking for healing implementation in the eyes, skin, and internal organ wounds. The review highlights all the different categories of hard and soft tissues that may be remediated with their contribution. The reader will also be exposed to the incorporation of methods for establishment of biomaterials, functionalization strategies, and the synthetic paths for organizing assemblies from biocompatible building blocks and natural metabolites.

Anti-barnacle biofouling coatings for the protection of marine vessels: synthesis and progress

Marine biofouling has gnawed both mobile and non-mobile marine structures since time immemorial, leading to the deterioration of designed operational capabilities as well as a loss of valuable economic revenues. Mitigation of biofouling has been the primary focus of researchers and scientists from across the globe to save billions of dollars wasted due to the biological fouling of marine structures. The availability of an appropriate environment along with favorable substrata initiates biofilm formation within a few minutes. The crucial element in establishing a gelatinous biofilm is the excreted metabolites of destructive nature and exopolymeric substances (EPSs). These help in securing as well as signaling numerous foulants to establish themselves on this substrate. The larvae of various benthic invertebrates adhere to these suitable surfaces and transform from juveniles to adult barnacles depending upon the environment. Despite biofouling being characteristically witnessed for a month or lengthier timeframe, the preliminary phases of the fouling process typically transpire on a much lesser timescale. A few natural and synthetic additives had demonstrated excellent non-toxic anti barnacle establishment capability; however, further development into commercial products is still far-fetched. This review collates the specific anti-barnacle coatings, emphasizing natural additives, their sources of extraction, general life cycle analysis, and concluding future perspectives of this niche product.

Hyperbranched polymers as superior adsorbent for the treatment of dyes in water

The effective control on environmental pollutants is crucial for the proper management of diverse environmental systems (e.g., soil, water, and air). In this respect, the utility of various functional materials such as hyperbranched polymers (HPs) has been recognized due to their great potentil as adsorbent for the mitigation of numerous environmental pollutants. Here, we highlight the latest progress achieved in the design and construction of HPs with high adsorption potentials. We focus on adsorption mechanisms, functionalization methods, the role of functional groups in adsorption capacity, and the choice of HPs in adsorption of cationic and anionic dyes. Recent published reports are reviewed to quantify and qualify the removal efficiency of pollutants through adsorption. We also evaluate the adsorbing efficiency of the constructed HPs and compared their performance with other such systems. The utilization potential of new materials (magnetic, polar, and biological) is highlighted along with the methods needed for their preparation and/or modification (surface, end-group, and zwitterionic) for the construction of efficient adsorbing systems. Finally, the advantages and limitations of adsorbing systems are described along with the existing challenges to help establish guidelines for future research. This article is thus expected to offer new path and guidance for developing advanced HP-based adsorbents.

Hyperbranched epoxy resin-grafted graphene oxide for efficient and all-purpose epoxy resin modification

Despite great efforts have been made on epoxy resins modification, development of additives that can be used to efficiently and universally modify epoxy composites remains a challenging task. Herein, graphene oxide (GO) sheets were covalently linked with hyperbranched epoxy resin (HBPEE-epoxy) to form HBPEE-epoxy functionalized GO (HPE-GO), which was then incorporated into epoxy resin (EP) matrix to achieve efficient and all-purpose enhancement of the properties of EPs. Compared with unmodified GO sheets, the functionalized HPE-GO sheets were better dispersed and exhibited better interfacial compatibility with the epoxy matrix, and consequently, the mechanical and thermal properties of HPE-GO/EP composites improved significantly compared to unmodified GO/EP composites. The tensile strength, flexural strength, impact strength, and fracture toughness (K_IC) of EP composites containing 0.5 wt% HPE-GO increased by 65.0%, 36.2%, 259.1%, and 178.9%, respectively, compared with those for the neat EP. The storage modulus (E'), glass transition temperature (T_g), and thermal stability (T_5%) also showed modest improvements. Furthermore, the HPE-GO/EP composites exhibited optimal thermal conductivities and thermal expansion properties, while maintaining higher volume resistivities compared with GO/EP composites. The results of this study support that HPE-GO is a promising, all-purpose modifier for EPs.

Design and fabrication of photoactive imidazole-based poly(ether-imide)s and a polyimide/HBP-modified SiO2 composite: toward high heat-resistance, antimicrobial activity and removal of heavy metal ions

This article describes the synthesis and properties of novel imidazole-based aromatic polyimides (PIs) containing bulky groups from direct polycondensation of two diamines with 3,3′,4,4′-benzophenone tetracarboxylic dianhydride (BTDA) and (hexafluoroisopropylidene)diphthalic anhydride (6FDA). The structure–property relationship of the prepared samples was fully determined via FT-IR, ¹H and ¹³C NMR and elemental analysis (CHN) techniques. The inherent viscosity values of the polyimides ranged from 0.51 to 0.73 dL g⁻¹. These PIs showed glass transition temperatures ranging from 273 to 306 °C, and 10% mass loss temperatures within the range of 478–504 °C in a N₂ atmosphere. High transparency with a UV-visible absorption cut-off wavelength was found to range between 285 and 300 nm. Good antimicrobial activity can be correlated with the presence of xanthene and imidazole units into the main structure of PIs. Next, SiO₂ nanoparticles as inorganic nanoparticles were added to one of the synthesized polyimides (BTDA-PIb), causing changes in the attributes of both the nanoparticles and PI. The data obtained from examining the properties of the prepared BTDA-PIb/HBP@SiO₂ demonstrated increased heat resistance, photoluminescence intensity, and antimicrobial inhibition compared to pure PI. Also, in this article, the polymeric samples as adsorbents were evaluated for extraction of heavy metal ions (Hg²⁺ and Co²⁺) from water sources.

Novel thermostable, photoactive, and solvable poly(ether-imide)s containing imidazole-based pendant groups and a BTDA-PIb/HBP@SiO₂ composite were synthesized and used due to their antimicrobial activity and as an adsorbent to remove heavy metal ions.