Effect of gamma irradiation on the interpenetrating networks of gelatin and polyacrylonitrile: Aspect of crosslinking using microhardness and crosslink density measurements

Abstract

ABSTRACT:The present article reports the effect of gamma irradiation on the hardness behavior of the interpenetrating polymer networks (IPNs) of gelatin and polyacrylonitrile (PAN). Various compositions of gluteraldehydecrosslinked gelatin and N, NЈ-methylene bis acrylamide (MBA)-crosslinked PAN were prepared and investigated for microhardness studies. The pre-and post-irradiated IPNs were characterized for their crosslinking density, determined with swelling ratio measurements. It was found that the crosslinked IPNs get further hardened because of radiational hardening at specific doses in the range from 2 to 250 kGy. The role of acrylonitrile and crosslinker (MBA) in the IPNs, as a consequence of irradiation, has also been explained. A fair consistency has been observed between the microhardness results and crosslinking density measurements.

Secondary chain motion and mechanical properties of γ‐irradiated‐regenerated cellulose films

“…γ‐Irradiation can be used for sterilization of the materials for applications related to food packaging or medical devices. Ionizing radiation upon interaction with polymers produces free radicals, ions, and highly reactive excited states; all of which can participate in several possible reactions including chain scission (degradation), cross‐linking, chain aggregation, sterilization, grafting, and oxidation reactions . Radiation‐induced modification of natural polymers includes generation of starch nanoparticles by γ‐irradiation of cassava and waxy maize .…”

Release of fluorescent markers from phase‐separated gelatin‐maltodextrin hydrogels

“…The following equation was derived for the swelling of an anionic hydrogel prepared in the presence of a solvent40: and for the swelling of a cationic hydrogel: where $ \overline M_{n} $ is the MW of the polymer without crosslinking, $ \overline M_{c} $ is the number‐average polymer MW between two adjacent crosslinks, $ \overline v $ is the specific volume of the hydrogel prior to swelling, V 1 is the molar volume of the solvent water (18 mL mol −1 ), v 2,s is the polymer volume fraction in the swollen state determined as roughly the inverse of the equilibrium swelling ratio, v 2,r is the polymer volume fraction in the relaxed state (the state of the polymer immediately after crosslinking but before swelling), I is the ionic strength, K a and K b are the dissociation constants for the acidic and basic moieties on the polymer, and χ 1 is the Flory‐Huggins parameter describing the polymer‐solvent interaction 6, 41. Using $ \overline M_{c} $ , the crosslink density, q , can be determined from42: …”

Synthesis, classification and properties of hydrogels: their applications in drug delivery and agriculture

“…, the state of the polymer after crosslinking but before swelling, v 2,s is the polymer volume fraction in the swelling state, roughly calculated by the reciprocal of the equilibrium swelling rate, I is the ionic strength, χ is the Flory–Huggins parameter that describes the interaction between the solvent and the polymer, and K b and K a are the dissociation constants of the basic and acidic parts of the polymer. 10,51 Using M c and M n , the swelling ratio q can be calculated as follows 52 :The parameter v 2,s is calculated from the volume swelling ratio, q v , 53 using the following formula:where the volume-swelling ratio was computed as 53 where ρ 1 and ρ 2 are the densities of the solvent and the polymer network, respectively. The weight swelling ratio q w can be calculated using the following formula 53 :where, m s and m o are the masses of the swollen and unswollen gel at equilibrium, respectively.…”