Background: Polymer composites with interpenetrated polymer network (IPN) structure are widely used as sound and vibration damping materials due to their high viscoelastic properties within the glass transition temperature range. In this study, polyurethane (PU)/poly (methyl methacrylate) (PMMA)-based interpenetrating polymer network with different ratios of PU to PMMA (i. e. 85: 15, 75: 25, and 65: 35) were prepared by in situ polymerization. Methods: The properties of as-prepared IPN and its components were evaluated by different scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and sound absorption. Tensile properties were also determined. As indicators of effective damping capability, viscoelastic parameters including loss factor (tan  ), glass transition temperature (Tg), and effective damping interval (tan  > 0. 3) were also determined. In order to determine the sound absorption coefficient in the prepared IPNs, a two-microphone impedance tube at the frequency of one octave was used. Results: The comparison of pure polymers (i. e. polyurethane and polymethyl methacrylate) and prepared IPNs indicated that the semi interpenetrated polymer network morphology was created through a broader range of tan  in different IPNs. Incorporation of PMMA into polyurethane in the form of interpenetrating polymer networks enhanced the damping acoustic properties of the semi-IPNs due to the permeability of the two polymers. In the temperature range of-50 to 11 ° C, both IPNs components showed high damping characteristics (tan   0. 3). Conclusions: Evaluation of the results indicated that the blends are capable of exerting viscoelastic effects for damping and sound attenuation.

Background: Polymer composites with interpenetrated polymer network (IPN) structure are widely used as sound and vibration damping materials due to their high viscoelastic properties within the glass transition temperature range. In this study, polyurethane (PU)/poly (methyl methacrylate) (PMMA)-based interpenetrating polymer network with different ratios of PU to PMMA (i. e. 85: 15, 75: 25, and 65: 35) were prepared by in situ polymerization. Methods: The properties of as-prepared IPN and its components were evaluated by different scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and sound absorption. Tensile properties were also determined. As indicators of effective damping capability, viscoelastic parameters including loss factor (tan  ), glass transition temperature (Tg), and effective damping interval (tan  > 0. 3) were also determined. In order to determine the sound absorption coefficient in the prepared IPNs, a two-microphone impedance tube at the frequency of one octave was used. Results: The comparison of pure polymers (i. e. polyurethane and polymethyl methacrylate) and prepared IPNs indicated that the semi interpenetrated polymer network morphology was created through a broader range of tan  in different IPNs. Incorporation of PMMA into polyurethane in the form of interpenetrating polymer networks enhanced the damping acoustic properties of the semi-IPNs due to the permeability of the two polymers. In the temperature range of-50 to 11 ° C, both IPNs components showed high damping characteristics (tan   0. 3). Conclusions: Evaluation of the results indicated that the blends are capable of exerting viscoelastic effects for damping and sound attenuation.

The antimicrobial activity of a wound dressing is a key factor for preventing and treating wound infection. The current study evaluated the physiochemical properties and antimicrobial activities of semi-IPNs (interpenetrating polymer networks) based on chitosan/polyvinyl alcohol (PVA) films and nanofibers as candidates for wound dressings and investigated the effects of morphologies (nanofibrous mats and films), crosslinking conditions of chitosan chains (uncrosslinked and crosslinked with genipin), and the presence of antibacterial drug (doxycycline) on their physicochemical and antibacterial properties. The morphology, chemical structure, fluid uptake, water vapor transmission rate, antimicrobial activity, and doxycycline release profile were assayed using SEM, FTIR spectroscopy, swelling test, permeation test, agar diffusion antibiogram, and dissolution test, respectively. The results demonstrated that crosslinking chitosan with genipin reduced the diameter of nanofibers, fluid uptake, and drug release from both nanofiber mats and film samples. According to the results, wound dressings with film morphology have better antimicrobial activity than those with nanofiber. The chitosan/PVA/Doxycycline 1% film has the potential for use as an antimicrobial wound dressing.

A series of novel interpenetrating polymer network (IPN) hydrogels based on soy protein (SP) and poly(acrylic acid) (PAA) were prepared with glutaraldehyde and N,N¢-methylenebisacrylamide (BIS) as the cross-linking agents. The structure and properties of the IPN hydrogels were characterized by FTIR, SEM, and DSC. The effects of pH and SP and BIS contents on the behaviour and release mechanism of the model drug bovine serum albumin (BSA) were also investigated in detail. The FTIR data indicated that the absorption of BSA into the IPN hydrogels is purely physical process. The SEM showed that changing the content of SP or BIS can influence the pore size and pore wall thickness of the hydrogels. The DSC data signify that all the hydrogels had good compatibility and miscibility, as well. It was also found that the release profiles of BSA strongly are dependent on the value of pH. The release percentage of BSA decreased with increasing the contents of SP or BIS. The BSA release profile followed Fickian diffusion pattern at pH below the pKa of PAA and the non- Fickian diffusion at pH above the pKa of PAA. The results showed that the IPN hydrogels are suitable candidates for colon drug delivery.