Effect of epichlorohydrin on the wet spinning of carrageenan fibers under optimal parameter conditions

Perspectives of nanofibrous wound dressings based on glucans and galactans - A review

Wound healing is a complex and dynamic process that needs an appropriate environment to overcome infection and inflammation to progress well. Wounds lead to morbidity, mortality, and a significant economic burden, often due to the non-availability of suitable treatments. Hence, this field has lured the attention of researchers and pharmaceutical industries for decades. As a result, the global wound care market is expected to be 27.8 billion USD by 2026 from 19.3 billion USD in 2021, at a compound annual growth rate (CAGR) of 7.6 %. Wound dressings have emerged as an effective treatment to maintain moisture, protect from pathogens, and impede wound healing. However, synthetic polymer-based dressings fail to comprehensively address optimal and quick regeneration requirements. Natural polymers like glucan and galactan-based carbohydrate dressings have received much attention due to their inherent biocompatibility, biodegradability, inexpensiveness, and natural abundance. Also, nanofibrous mesh supports better proliferation and migration of fibroblasts because of their large surface area and similarity to the extracellular matrix (ECM). Thus, nanostructured dressings derived from glucans and galactans (i.e., chitosan, agar/agarose, pullulan, curdlan, carrageenan, etc.) can overcome the limitations associated with traditional wound dressings. However, they require further development pertaining to the wireless determination of wound bed status and its clinical assessment. The present review intends to provide insight into such carbohydrate-based nanofibrous dressings and their prospects, along with some clinical case studies.

Non-Toxic Crosslinking of Electrospun Gelatin Nanofibers for Tissue Engineering and Biomedicine-A Review

Electrospinning can be used to prepare nanofiber mats from diverse polymers, polymer blends, or polymers doped with other materials. Amongst this broad range of usable materials, biopolymers play an important role in biotechnological, biomedical, and other applications. However, several of them are water-soluble, necessitating a crosslinking step after electrospinning. While crosslinking with glutaraldehyde or other toxic chemicals is regularly reported in the literature, here, we concentrate on methods applying non-toxic or low-toxic chemicals, and enzymatic as well as physical methods. Making gelatin nanofibers non-water soluble by electrospinning them from a blend with non-water soluble polymers is another method described here. These possibilities are described together with the resulting physical properties, such as swelling behavior, mechanical strength, nanofiber morphology, or cell growth and proliferation on the crosslinked nanofiber mats. For most of these non-toxic crosslinking methods, the degree of crosslinking was found to be lower than for crosslinking with glutaraldehyde and other common toxic chemicals.

High-strength carrageenan fibers with compactly packed chain structure induced by combination of Ba2+ and ethanol

Carrageenan fibers have attractive applications in textile, but their low strength remains a problem that needs to be urgently addressed. In this work, a novel facile, environmental friendly method for fabricate high-strength carrageenan fibers is proposed. It involves the crosslinking of a small amount of Ba²⁺ ions in the carrageenan solution, followed by using recyclable alcohol in coagulation and stretching baths. Carrageenan molecular chains were allowed to first sufficiently interact with metal barium ions, and then were stretched and dehydrated with alcohol to increase the hydrogen bonding interaction between the molecular chains. As a result, the carrageenan fibers with high-strength ionic and hydrogen bonds were obtained. The fibers obtained by the novel method had high tensile strength at 1.63 cN/dtex, which is two times higher than that of those obtained by the traditional process.

Comparison of Two Different Preparation Methods of Wet-Spun Carrageenan Fibers Directly from Chondrus Extractions

In order to improve the characters of carrageenan fibers, two different process methods were presented in this study. Dopes prepared directly from Chondrus extraction by Route A-adding NaOH after Chondrus extraction-or Route B-using NaOH solution to extract Chondrus and carrageenan fibers (Fibers A and Fibers B)-were obtained using the wet spinning process using barium chloride as the coagulant at room temperature. The properties of dopes were studied by dynamic light scattering and gel permeation chromatography. The properties of Fibers A and Fibers B were comprehensively studied by Fourier transform infrared, thermal analysis, scanning electron microcopy, and tensile testing. The results showed that carrageenan with a larger molecule weight in Dope A and Fibers A showed higher intensity, better morphology, and stable thermal properties.

Carrageenan as a dry strength additive for papermaking

Carrageenans are commercially important sulfated gums found in various species of red seaweeds (Rhodophyta), wherein they serve a structural function similar to that of pectins in land plants. In this study, carrageenan was used independently or in combination with cationic polyacrylamide (CPAM) and/or Al₂(SO₄)₃ to explore its application as a dry strength additive in papermaking. Strength index determination, ash content detection, FTIR characterization and SEM observation were performed on prepared handsheets. The results showed that with 0.6% Al₂(SO₄)₃ and 0.2% carrageenan as additives, the tensile index increased by 13.53% and precipitated calcium carbonate (PCC) retention increased by 57.06%. With 0.6% Al₂(SO₄)₃, 0.2% carrageenan and 0.03% CPAM as additives, PCC retention increased by 121% while the tensile index did not fall compared to handsheets without additives, indicating that carrageenan could enhance the strength of handsheets and be used as an anionic dry strength agent.

Pyrolysis products and thermal degradation mechanism of intrinsically flame-retardant carrageenan fiber

Carrageenan fiber (CAF) was prepared by a wet spinning method to develop an excellent flame-retardant material.