Hotspots, Frontiers, and Emerging Trends of Superabsorbent Polymer Research: A Comprehensive Review

Superabsorbent polymer (SAP) is a kind of functional macromolecule with super-high water absorption and retention properties, which attracts extensive research and has wide application, especially in the areas of hygiene and agriculture. With reference to the Web of Science database, the SAP research literature from 2000 to 2019 is reviewed both quantitatively and qualitatively. By examining research hotspots, top research clusters, the most influential works, the representative frontier literature, and key emerging research trends, a visual panorama of the continuously and significantly increasing SAP research over the past 2 decades was presented, and issues behind the sharp increase in the literature were discovered. The findings are as follows. The top ten keywords/hotspots headed by hydrogel highlight the academic attention on SAP properties and composites. The top ten research themes headed by clay-based composites which boast the longest duration and the strongest impact have revealed the academic preference for application rather than theoretical study. Academically influential scholars and research studies have been acknowledged, and the Wu group was at the forefront of the research; however, more statistically significant works have been less detected in the last 10 years despite the sharper increase in publications. Hydrogel, internal curing, and aerogel are both current advances and future directions.

Reviewing Chitin/Chitosan Nanofibers and Associated Nanocomposites and Their Attained Medical Milestones

Chitin/chitosan research is an expanding field with wide scope within polymer research. This topic is highly inviting as chitin/chitosan’s are natural biopolymers that can be recovered from food waste and hold high potentials for medical applications. This review gives a brief overview of the chitin/chitosan based nanomaterials, their preparation methods and their biomedical applications. Chitin nanofibers and Chitosan nanofibers have been reviewed, their fabrication methods presented and their biomedical applications summarized. The chitin/chitosan based nanocomposites have also been discussed. Chitin and chitosan nanofibers and their binary and ternary composites are represented by scattered superficial reports. Delving deep into synergistic approaches, bringing up novel chitin/chitosan nanocomposites, could help diligently deliver medical expectations. This review highlights such lacunae and further lapses in chitin related inputs towards medical applications. The grey areas and future outlook for aligning chitin/chitosan nanofiber research are outlined as research directions for the future.

EMERGING ADVANCES IN RUBBER TECHNOLOGY BY THE SUITABLE APPLICATION OF SOL-GEL SCIENCE AND TECHNOLOGY

ABSTRACT In recent years, the application of sol-gel science to industrial polymer research has offered advancements in rubber technology. The use of sol-gel–synthesized materials for the development of highly reinforced rubber composites is the most commonly adopted and popular method exercised by rubber scientists. This article comprehensively reviews the recent progress regarding preparation and properties of sol-gel–synthesized nanoparticles-based rubber composites. The pragmatic consequences of sol-gel–synthesized nanoparticles in rubber compounds are systematically described through rheological, mechanical, and thermal properties. Emphatic focus is given to understanding the reinforcement mechanism of rubber composites by the use of sol-gel–derived alkoxide silica as filler. The properties of rubber nanocomposites are usually dependent on the dispersion of sol-gel–synthesized nanoparticles into the rubber matrix. The results reviewed from prolific studies suggested that sol-gel science has tremendous potential to develop high performance rubber nanocomposites for future industrial application.

Melanin, the What, the Why and the How: An Introductory Review for Materials Scientists Interested in Flexible and Versatile Polymers

Today, western society is facing challenges to create new medical technologies to service an aging population as well as the ever-increasing e-waste of electronic devices and sensors. A key solution to these challenges will be the use of biomaterials and biomimetic systems. One material that has been receiving serious attention for its biomedical and device applications is eumelanin. Eumelanin, or commonly known as melanin, is nature’s brown-black pigment and is a poly-indolequinone biopolymer, which possess unique physical and chemical properties for material applications. Presented here is a review, aimed at polymer and other materials scientists, to introduce eumelanin as a potential material for research. Covered here are the chemical and physical structures of melanin, an overview of its unique physical and chemical properties, as well as a wide array of applications, but with an emphasis on device and sensing applications. The review is then finished by introducing interested readers to novel synthetic protocols and post synthesis fabrication techniques to enable a starting point for polymer research in this intriguing and complex material.

Macrocycles in dual role: ancillary ligands in metal complexes and organocatalysts for the ring-opening polymerization of lactide

In the twenty-first century, one of the central focus of polymer research in academia and industries is directed towards the design of environmentally-benign materials produced from reagents that have minimal deleterious effects on our environment. The aliphatic polyester PLA is one such example. Due to its biodegradable, biorenewable and biocompatible nature, PLA finds diverse applications, especially in the biomedical field. PLA is exclusively synthesized by the ring-opening polymerization of lactide (cyclic dimer of lactic acid) in the presence of a catalyst. The macrocycles and macrocyclic metal moieties can act as effective catalysts for the polymerization resulting in the formation of PLA with controlled tacticity and predetermined molecular weight. This review reports metal-based catalytic systems supported by porphyrin, calixarene and bispyrrolidine- salan as ancillary ligand and metal-free organocatalyst sparteine for the ROP of LA. The variation in catalytic activity, tacticity of PLA, and PLA's molecular weight distribution by substitutional changes in the catalyst framework have been discussed in detail. Graphic abstract

The nonequilibrium behaviors of covalent adaptable network polymers during the topology transition

Vitrimer with bond exchange reactions (BERs) is a type of covalent adaptable network (CANs) polymers at the forefront of recent polymer research. They exhibit malleable and self-healable behaviors and combine...