Facile preparation of monolithic κ-carrageenan aerogels

Abstract

To the best of our knowledge, it is the first study reporting the synthesis of monolithic κ-carrageenan aerogels with meso- and macroporous structures, being unique in physical and chemical properties. We demonstrate a novel method to synthesize κ-carrageenan aerogels in which potassium thiocyanate was used as the source of specific ions. Aerogels were characterized by envelope density analysis, scanning electron microscopy, nitrogen adsorption-desorption analysis, X-ray powder diffractometry and IR spectroscopy. By varying the concentration of κ-carrageenan between 0.5 and 3 wt%, the envelope density can be linearly increased from 40 to 160 kg m⁻³. The sulphate functional groups in the wet gel and the specific ions are the key factors controlling the volume shrinkage of aerogels which average about 66%. The aerogels exhibit a fibrillar structure similar to cellulose aerogels. The fibril thickness was observed to be 10-15 nm and the specific surface area was about 230 m² g⁻¹. The existing meso- and macroporous structures were confirmed by nitrogen adsorption-desorption isotherm analysis and scanning electron microscopy. The aerogels were completely pure, free of specific ions and confirmed to be amorphous by powder X-ray diffraction. Hence, these porous materials can provide a matrix with a chelating function which can be used as a host in many applications.

Facile Preparation of Nanofibrillar Networks of “Ureido‐Chitin” Containing Ureido and Amine as Chelating Functional Groups

“…Offering the host-guest chemical relation, aerogelso fp olysaccharide materials with chelating functional groups can be employed as carrier/supportings ystemsi n many applicationsi ncluding catalysis, separationa nd sensing techniques andb iomedicines. [1] Through our ongoing research work exploring methods to prepare aerogels of polysaccharides with chelating functions, [2] we have established that new aerogel materials with desirable featuress uch as resistancet o acidic and alkaline media are required.T he new sustainable features of aerogels may allow the materials to be used again after their function in applications. Recent reports [3] of nanomaterials showedt he development of sustainable features with ah igh efficiency hosting property,w hich have only been achieved after chemically modifying the available functional groups of polysaccharides.…”

Seaweed‐derived κ‐carrageenan: Modified κ‐carrageenan as a recyclable green catalyst in the multicomponent synthesis of aminophosphonates and polyhydroquinolines

“…Among them, α‐, β‐, γ‐, κ, ι‐, and θ‐carrageenan are more stable than the others under alkali conditions . Moreover, There are many applications for carrageenans; these include their use in the food industry and hydrogel and aerogel manufacturing . KCAR can also make a complex with other types of polymers to improve mechanochemical properties .…”

“…11 Moreover, There are many applications for carrageenans; these include their use in the food industry 12 and hydrogel and aerogel manufacturing. 13,14 KCAR can also make a complex with other types of polymers to improve mechanochemical properties. [15][16][17][18] The other applications of KCAR include biological studies and drug-delivery cases.…”

Random photografting of polymers to nanoparticles for well‐dispersed nanocomposites

“…1,2 In many cases, the state of particle dispersion is critical to the composite properties, and thus, the subject of controlling aggregation or dispersion has gained much attention. [3][4][5][6][7][8][9][10][11][12][13][14][15][16] Several basic methods are used to achieve well-dispersed nanocomposites. Perhaps the simplest approach relies on attractive interactions between functional groups in the (co)polymer matrix and the particle surface to decrease the driving force for aggregation; [17][18][19][20][21] however, as the interaction strength is highly dependent on the chemistry of both the (co)polymer and the particle surface, this technique is not easily generalized.…”

“…Perhaps the largest body of experimental and theoretical work surrounds the use of endgrafted homopolymers that are chemically identical to the matrix polymer, which yields dispersion for moderate graft densities and sufficiently large lengths of the grafted chains. [3][4][5][6][7][8][9][10][14][15][16]22 Attractive interactions between the ligands and the polymer matrix have also been used to afford dispersion in several cases. 11,12,23,24 Although effective, the reliance on end-grafted polymers of controlled molecular weight means that such approaches can be synthetically challenging and are likely not suitable for all types of particles and polymers.…”