Inorganic silica functionalized with PLLA chains via grafting methods to enhance the melt strength of PLLA/silica nanocomposites

The low melt strength greatly limits the application of PLA as biodegradable package materials produced by film blowing method. Modified silica nanoparticles are introduced into PLA matrix to solve this problem in this study. To build Poly (l-lactide) nanocomposites successfully, two kinds of convenient and efficient methods are conducted to synthesize well-defined topological PLLA grafted SiO₂ nanoparticle. One is the ring-opening of l-lactide (Grafting from), and another is nucleophilic addition reaction (Grafting to). The structure, molecular weight of grafted PLLA chains, grafting density, and the thermal decomposition behavior of the nanoparticles prepared by different methods are characterized. By varying the contents of the initiator SiO₂ and the molecular weight of the reacted PLA chains, high density-low molecular weight PLLA grafted SiO₂ are obtained in “grafting from” while high molecular weight-low grafting density PLLA grafted SiO₂ are synthesized in “grafting to”. It is exactly in good agreement with the theoretic model. The spatial distribution of nanoparticles as well as the interaction force between nanoparticles and matrix is critical important to structuring bionanocomposites with desirable properties. So the two kinds of synthesized nanoparticles are introduced into PLA matrix in our contribution to evaluate these two factors, respectively. The TEM and SEM results both reveal the uniform dispersion of nanoparticles after modified. While the extension and shear rheology results show that the long grafted chains covalently connected on the surface of the silica via “grafting to” contribute more to enhance the melt strength of PLA. Meanwhile, stabilized PLA nanocomposites films with modified silica via “grafting to” method are successfully blown base on these researches. The research in this work constitutes a robust way to design melt-strengthen PLA/SiO₂ nanocomposites.     

Preparation and characterization of poly(ϵ‐caprolactone‐co‐p‐dioxanone)–poly(ethylene glycol)–poly(ϵ‐caprolactone‐co‐p‐dioxanone)/bioactive inorganic particle nanocomposites

With an aim to develop injectable hydrogel with improved solution stability and enhanced bone repair function, thermogelling poly(ε‐caprolactone‐co‐p‐dioxanone)‐poly(ethylene glycol)‐poly(ε‐caprolactone–co‐p‐dioxanone) (PECP)/bioactive inorganic particle nanocomposites were successfully prepared by blending the triblock copolymer (PECP) with nano‐hydroxyapatite (n‐HA) or nano‐calcium carbonate (n‐CaCO₃). The hydrogel nanocomposites underwent clear sol–gel transitions with increasing temperature from 0 to 50°C. The obtained hydrogel nanocomposites were investigated by ¹H NMR, FT‐IR, TEM, and DSC. It was found that the incorporation of inorganic nanoparticles into PECP matrix would lead to the critical gelation temperature (CGT) shifting to lower values compared with the pure PECP hydrogel. The CGT of the hydrogel nanocomposites could be effectively controlled by adjusting PECP concentration or the content of inorganic nanoparticles. The SEM results showed that the interconnected porous structures of hydrogel nanocomposites were potentially useful as injectable scaffolds. In addition, due to the relatively low crystallinity of PECP triblock copolymer, the aqueous solutions of the nanocomposites could be stored at low temperature (5°C) without crystallization for several days, which would facilitate the practical applications. The PECP/bioactive inorganic particle hydrogel nanocomposites are expected to be promising injectable tissue engineering materials for bone repair applications. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Interface of polyimide–silica grafted with different silane coupling agents: Molecular dynamic simulation

In this article, the effects of different silane coupling agents: 3‐glycidyloxypropyltrimethoxysilane (GOTMS), 3‐aminopropyltriethoxysilane (APTES), and 3‐methacryloxypropyltrimethoxysilane (MPTS), on the interface between polyimide (PI) and silica (SiO₂), were investigated using molecular dynamic simulation. The results indicate that binding energy between PI molecules and SiO₂ surface mainly comes from van der Waals interaction. Proper silane coupling agents generate a thin membrane on the surface of SiO₂, which improves the thickness of the transition layer between PI molecules and SiO₂ surface. And density of the transition layer was enhanced by APTES significantly. In addition, amino group (? NH₂) improves the electrostatic interaction between PI molecules and SiO₂ surface rather than epoxy group (? CH? CH₂? O) and methacrylic oxide group (? O? CO? C(CH₃)?CH₂). As a result, APTES enhances the binding energy effectively. However, excessive silane coupling agent increases the distance between PI matrices and SiO₂, which deteriorates performance of the interface. In addition, GOTMS and MPTS generate a thick and dense membrane on SiO₂ surface, which induces the loose transition layer and poor binding energy. Overlap parameter between PI molecules and SiO₂ surface grafted with silane coupling agent can be employed to evaluate the transition layer successfully. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45725.     

Thermal properties and crystallinity of PCL/PBSA/cellulose nanocrystals grafted with PCL chains

Bionanocomposite films of poly(?‐caprolactone) (PCL) and poly(butilene succinate‐co ‐adipate) (PBSA) blends with cellulose nanocrystals (CNW) grafted with PCL chains (CNW‐g ‐PCL) were prepared by solution casting and their thermal properties and crystallinity were studied. The CNW surface was modified with PCL chains by grafting “from” approaches, in an effort to improve their compatibility with the polymer blends. The grafting efficiency was evidenced by FTIR and TGA analysis. The acicular morphology of CNW‐g ‐PCL was characterized by SEM. The TGA results showed an increase in the thermal stability of the CNW grafted with PCL chains. The PCL/PBSA blends showed higher thermal stability in comparison with the neat polymers and PCL/PBSA/CNW‐g ‐PCL bionanocomposites. DSC results showed the CNW‐g ‐PCL act as a nucleating agent in the bionanocomposites. Additionally, a better interaction of the CNW‐g ‐PCL in the blends of 30/70 composition in comparison with the blends of 50/50 composition was characterized. The results obtained for aforementioned films prepared by solution casting encourage the production of such bionanocomposites by melt compounding (extrusion), aiming the achievement of new bionanocomposites materials with improved thermal and mechanical properties. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44493.     

Integrated PLGA–Ag nanocomposite systems to control the degradation rate and antibacterial properties

Biodegradable polymer based nanocomposite materials have attracted much attention since they can be used for biomedical and pharmaceutical applications. In order to have highly integrated PLGA nanocomposite materials, silver colloidal nanoparticles were prepared in chloroform starting from silver nitrate and using polyvinylpyrrolidone as reduction and capping agent. TEM and AFM imaging give information on the size distribution of the silver nucleus (7.0 nm) and the capping shell (8.2–10.7 nm). PLGA–Ag nanocomposites were prepared upon addition of 1 or 3% wt of silver nanoparticles to the PLGA/chloroform suspension. The effect of silver loading on polymer degradation was studied following the mass loss and the morphology of nanocomposite films at different degradation stages. The concentrations of Ag⁺, which is released during nanocomposite degradation, were monitored and analyzed through the diffusion model, to have insight on the degradation kinetics. The release rate, and likely the degradation rate, was reduced at higher silver loading. Bacterial growth tests indicated that the cell growth is inhibited in the presence of PLGA–Ag nanocomposites and the efficiency is correlated to Ag⁺ release. Thus, controlling the nanoparticle loading, a tunable degradation and antibacterial action can be designed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1185‐1193, 2013     

Influence of a sorbitol‐based nucleating agent modified with silsesquioxanes on the non‐isothermal crystallization of isotactic polypropylene

This article investigates the effect of modifying the polypropylene (iPP) α‐phase nucleating agent 1,3:2,4‐bis(3,4‐dimethylbenzylidene) sorbitol (DMDBS) with tetrasilanolphenyl silsesquioxane (phPOSS). It has been proven that an increasing amount of silsesquioxane leads to differences in the crystallization behavior. What is more, it has been observed that the nucleation effect that results from the addition of sorbitol derivatives is suppressed by phPOSS activity. To understand the influence of phPOSS addition on the crystallization kinetics of PP/DMDBS/phPOSS composites that have been prepared by melt processing in a twin screw extruder, differential scanning calorimetry, rotational rheometry and Fourier transform infrared spectroscopy are performed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40131.     

Effect of nano‐silica on the mechanical,thermal, and crystalline properties of poly(vinyl alcohol)/nano‐silica films

Poly(vinyl alcohol)/nano‐silica (PVA/nano‐SiO₂) films were prepared through extrusion blowing with the addition of water and glycerin as plasticizer. The characteristic properties of PVA/nano‐SiO₂ films were investigated by differential scanning calorimetry, dynamic mechanical analysis, Haake torque rheometry, and atomic force microscopy (AFM). The results showed that the mechanical properties of PVA/nano‐SiO₂ were improved dramatically. The tensile strength of the nanofilms increased from 62 MPa to 104 MPa with loading 0.3 wt % nano‐SiO₂ and the tear strength was improved from 222 KN/m to 580 KN/m. The crystallinity of the films loaded with 0.4 wt. % nano‐SiO₂ decreased from 32.2% to 21.0% and the AFM images indicated that the amorphous region of nanofilms increased with increasing nano‐SiO₂ content. The storage modulus and loss modulus increased to two and nearly three times with 0.3 wt % nano‐SiO₂ loading. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Thin film composite forward osmosis membranes with poly(2‐hydroxyethyl methacrylate) grafted nano‐TiO2 as additive in substrate

The poly(2‐hydroxyethyl methacrylate) grafted titanium dioxide nanoparticles were synthesized and added to the substrate of flat‐sheet thin film composite forward osmosis (TFC‐FO) membranes. The hydrophilicity of substrate was improved, which was advantageous to enhance the water flux of TFC‐FO membranes. The membranes containing a 3 wt % TiO₂‐PHEMA in the substrate exhibited a finger‐like structure combined with sponge‐like structure, while those with lower or without TiO₂‐PHEMA content showed fully finger‐like structures. As for FO performance, the TFC‐FO membranes with 3 wt % TiO₂‐PHEMA content achieved the highest water flux of 42.8 LMH and 24.2 LMH against the DI water using 2M NaCl as the draw solution tested under the active layer against draw solution (AL‐DS) mode and active layer against feed solution (AL‐FS) mode, respectively. It was proven that the hydrophilic property of membrane substrates was a strong factor influencing the water flux in FO tests. Furthermore, the structural parameter was remarkably decreased with an increase of TiO₂‐PHEMA content in membrane substrate, indicating the reducing of internal concentration polarization. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43719.     

Application of shear thickening fluid in ultra high molecular weight polyethylene fabric

An advanced stab‐resistant material composed of shear thickening fluid (STF) and ultra high molecular weight polyethylene (UHMWPE) fabric was investigated. STF was prepared by dispersing nanosilica (SiO₂) into ethylene glycol. The shear thickening behavior of STF with the increase of the shear rate was observed by PhysicaMCR301. STF/UHMWPE composite fabric was synthesized by impregnating UHMWPE fabric in STF dilution. Stab resistant experiment was conducted on a self‐made stab test machine with knife and spike as stab tool. The results demonstrate that the stab resistant property of the UHMWPE fabric is greatly improved by impregnating STF. The stab resistant property is greatly increased with the increase of mass fraction of silica in STF. Especially, when the mass fraction of SiO₂ in STF is 38%, the stab resistance force and energy absorption of STF/UHMWPE are optimal for knife and spike threats. With the same stab resistant properties, the flexibility of UHMWPE fabric impregnated with STF is higher than that of the neat fabric. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Melt extruded nanocomposites of polybutylene adipate‐co‐terephthalate (PBAT) with phenylbutyl isocyanate modified cellulose nanocrystals

Traditional commodity polymers are widely used in several disposable or short‐life items and take hundreds of years to decompose in nature. These polymers could be replaced in several uses by biodegradable polymers, like polybutylene adipate‐co‐terephthalate (PBAT) studied in this work. For this, nonetheless, it is necessary to improve some of the PBAT properties, like mechanical resistance and barrier properties. In this work, cellulose nanocrystals (CNC) were incorporated in PBAT with this intention, through melt extrusion. Aiming to avoid CNC aggregation during the drying and extrusion process, a CNC chemical modification with phenylbutyl isocyanate was done. It was possible to obtain PBAT‐CNC melt extruded composites with an elastic modulus 55% higher and water vapor permeability 63% lower than the values of the pure polymer, without compromising PBAT biodegradation. Therefore, the composites prepared with these enhanced properties have great potential as substitutes for traditional commodity polymers. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43678.     

Mechanical properties study of micro‐ and nano‐hydroxyapatite reinforced ultrahigh molecular weight polyethylene composites

This is a comparative study between ultrahigh molecular weight polyethylene (UHMWPE) reinforced with micro‐ and nano‐hydroxyapatite (HA) under different filler content. The micro‐ and nano‐HA/UHMWPE composites were prepared by hot‐pressing method, and then compression strength, ball indentation hardness, creep resistance, friction, and wear properties were investigated. To explore mechanisms of these properties, differential scanning calorimetry, infrared spectrum, wettability, and scanning electron microscopy with energy dispersive spectrometry analysis were carried out on the samples. The results demonstrated that UHMWPE reinforced with micro‐ and nano‐HA would improve the ball indentation hardness, compression strength, creep resistance, wettability, and wear behavior. The mechanical properties for both micro‐ and nano‐HA/UHMWPE composites were comparable with pure UHMWPE. The mechanical properties of nano‐HA/UHMWPE composites are better compared with micro‐HA/UHMWPE composites and pure UHMWPE. The optimum filler quantity of micro‐ and nano‐HA/UHMWPE composites is found to be at 15 wt % and 10 wt %, separately. The micro‐ and nano‐HA/UHMWPE composites exhibit a low friction coefficient and good wear resistance at this content. The worn surface of HA/UHMWPE composites shows the wear mechanisms changed from furrow and scratch to surface rupture and delamination when the weight percent of micro‐ and nano‐HA exceed 15 wt % and 10 wt %. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42869.     

Ionic‐liquid‐assisted three‐dimensional caged silica ablative nanocomposites

In this study, we demonstrated a novel three‐dimensional network of thermally stable fumed silica (FS)–resorcinol formaldehyde (RF) nanocomposites via an ionic‐liquid (IL)‐assisted in situ polycondensation process. The study involved subjecting the tailored nanocomposites to thermogravimetric analysis and oxyacetylene flame environment as per ASTM test standards for thermal ablative performance. X‐ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, high‐resolution transmission electron microscopy, Raman spectroscopy, and wettability studies were undertaken to underline the improvement correlation in the microstructure and material properties. Significant reductions in the linear ablation rate (66%) and mass ablation rate (26.6%), along with lower back‐face temperature profiles, marked enhanced ablative properties. The increased char yield (33.3%) and higher temperatures for weight losses evinced the improved thermal stability of the modified RF resin. The uniformly dispersed fused nanosilica with a glassy coating morphology on the ablative surface acted as barrier to oxidation. The results signify that the IL‐assisted modification of the RF resin with FS significantly enhanced ablative performance. A viable replacement to the conventional phenolic nanocomposites for thermal ablative applications to buy critical time for the containment and suppression of thermal‐heat‐flux threats is of paramount importance. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45328.     

Crystallization kinetics,morphology, and hydrolytic degradation of novel bio‐based poly(lactic acid)/crystalline silk nano‐discs nanobiocomposites

In this work, novel biodegradable crystalline silk nano‐discs (CSNs) having a disc‐like morphology have been utilized for fabrication of poly(lactic acid) (PLA) nanocomposites by melt‐extrusion. The main focus is to investigate the effect of CSN on isothermal melt crystallization kinetics, spherulitic growth rates, morphology, and hydrolytic degradation of PLA. Spherulitic morphology and growth rates are examined over a wide range of crystallization temperatures (90–120 °C). With incorporation of CSN, the isothermal crystallization kinetics of PLA/CSN increases, however, the crystallization mechanism remains unaltered. The apparent activation energy and surface energy barrier for crystallization process decreases upon addition of CSNs. At lower isothermal crystallization temperatures (T_c) viz. (90–100 °C), reduced growth rates of PLA spherulites is observed. Both PLA and PLA/CSN exhibit highest crystallization rates at around ～107 °C. The hydrolytic degradation rates calculated from molecular weight reduction shows that PLA/CSN nanocomposites' degradation rates are lower as compared to PLA in acidic, neutral, and alkaline media at pH = 2, 7, and 12, respectively, due to hydrophobic nature of CSN. Scanning electron microscopy study demonstrated the surface erosion mechanism of hydrolytic degradation of PLA and PLA/CSN nanocomposites. This work provides valuable insight for the application and reclamation of PLA/CSN bionanocomposites in moist and wet working environments. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46590.     

Antibacterial activity and cytotoxicity of hydrogel–nanosilver composites based on copolymers from 2‐acrylamido‐2‐methylpropanesulfonate sodium

In this research, we contributed to the search for potential hydrogel–silver dressings by generating hydrogel–silver nanoparticles (AgNPs) composites prepared by the dipping of the crosslinked hydrogel poly(N‐vinylpyrrolidone‐co‐2‐acrylamido‐2‐methylpropanesulfonate sodium) (1:1) and poly(acrylamide‐co‐2‐acrylamido‐2‐methylpropanesulfonate sodium) (1:1) into an aqueous suspension of citrate‐stabilized AgNPs. The composites obtained were evaluated by an antibacterial activity assay on Staphylococcus aureus and Escherichia coli and subjected to an in vitro cytotoxicity assay for human fibroblasts. The composite formed from the hydrogel poly(N‐vinylpyrrolidone‐co‐2‐acrylamido‐2‐methylpropanesulfonate sodium) with 3 mol % N,N‐methylene bisacrylamide showed the highest antibacterial activity and the least cytotoxicity among the composites tested; this makes it an excellent alternative as a potential dressing for the treatment of deep and exudative wounds. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39644.     

Preparation and characterization of polybutylene‐succinate/poly(ethylene‐glycol)/cellulose nanocrystals ternary composites

Ternary composites were prepared by twin screw extrusion from polybutylene‐succinate (PBS), poly(ethylene‐glycol) (PEG), and cellulose nanocrystals (CNC). The aim of the work is to improve the physical–mechanical properties of PBS by the addition of CNC. A PEG/CNC masterbatch was prepared in order to achieve a good dispersion of hydrophilic CNC in the hydrophobic PBS. The influence of the nanoparticle content on the polymer properties was studied. Regarding the thermal properties fractioned crystallization phenomena of PEG was observed during cooling from the melt. No significant nucleating effect of the nanocellulose was observed. The material containing 4 wt % of CNC showed the best mechanical performance among the nanocomposites studied due to the combination of high modulus and elongation at break with a low detrimental in strength compared with the PBS/PEG blend. Moreover, no nanocellulose agglomerations were observed in its FESEM micrograph. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43302.     

Polylactide and hybrid silicasol nanoparticle‐based composites

The effects of the chemical nature and size of the hybrid nanoparticle external layer on the structures and properties of polylactide composites are investigated. Polylactide is used as the matrix polymer, and molecular silicasol particles with γ‐hydroxypropylic, (methoxyacetyl)oxy, and acetoxy surface groups serve as fillers. A preliminary assessment of the thermodynamic compatibility of polylactide with the surface groups of molecular silicasols is performed. The hydrophilic shells of the silicasols prevent their aggregation in the bulk of the nanocomposite. It shows variations in the chemical structure of the surface layer of the nanoparticles as well as their sizes and concentration make it possible to conduct a controlled change of the characteristics of the composites, particularly to eliminate one of the drawbacks of PLA, the low speed of its crystallization. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41894.     

Effect of silk nano‐disc dispersion on mechanical,thermal, and barrier properties of poly(lactic acid) based bionanocomposites

Exacerbated environmental concerns about petroleum‐based plastics provide the impetus to foster sustainable poly(lactic acid) (PLA) based food packaging. Nonetheless, PLA has its foibilities such as its brittleness, higher gas permeability, and slow crystallization. With the intent to mitigate the above shortcomings, we report a maiden effort for the fabrication of PLA/crystalline silk nano‐discs (CSNs) based bionanocomposites by melt‐extrusion for high temperature engineering and food packaging applications. Acid hydrolyzed silk fibroin from muga silk (Antheraea assama) yields CSNs, a crystalline hydrophobic discotic nanofiller with diameter of ～50 nm and thickness ～3 nm. At optimum loadings of 1 wt % uniform dispersed CSNs with percolated network structures covering the entire matrix can be seen. Due to enhanced crystal nucleation density, water vapor, and oxygen permeability reduced by ～30% and ～70%, respectively. Enhancement in toughness, percentage elongation, and tensile strength up to ～65%, ～40%, and ～10%, respectively, is obtained. Onset of thermal decomposition for the PLA/CSN improved ～10 °C, confirming the role of CSN in enhancing melt stability. Accordingly, this investigation renders a novel non‐invasive approach for increasing the crystallinity with improvement in thermomechanical and barrier properties which make this bionanocomposite, a promising candidate for food packaging applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46671.     

Cellulose nanocrystal driven crystallization of poly(d,l‐lactide) and improvement of the thermomechanical properties

The technological exploitation of polylactide in fields requiring wide range of operating conditions is limited by the low crystallization rate of the polymer and therewith the low thermomechanical stability. Here we report the crystallization and consequent improvement of the thermomechanical properties of originally amorphous poly(d,l ‐lactide) (d : l ratio 11 : 89) loaded with cellulose nanocrystals (CNCs). Isothermal treatment of samples with different CNC contents and at various temperatures, showed up to 6 wt % crystalline phase formation, as confirmed by differential scanning calorimetry and X‐ray diffraction measurements. Under a particular set of annealing conditions, CNCs promote the formation of a lamellar structure. This provides the system with higher order and cohesion which in combination with stress‐transfer between CNCs, led to an increase of the storage modulus in the rubbery plateau up to 30 times (from 2.7 MPa up to 79 MPa), a rise of the melting temperature up to 50°C, and an improvement of the Young's modulus up to 40%. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41607.     

Morphology and crystallization behavior of PCL/SAN blends containing nanosilica with different surface properties

Morphology and crystallization behavior of poly(?‐caprolactone) (PCL) in its 80/20 blends with poly(styrene‐co‐acrylonitrile) (SAN) containing hydrophobic or hydrophilic nanosilica was investigated. It was found that hydrophilic nanosilica displayed a more significant refinement effect on co‐continuous morphology of PCL/SAN blends than hydrophobic nanosilica for its selective distribution within the PCL matrix but closer to the two‐phase interface. Ring‐banded spherulites were observed in both kinds of nanosilica‐filled blends, the periodic distance of which decreased with increasing nanosilica content. Hydrophilic nanosilica reduced the dependence of the periodic distance of ring‐banded spherulites on the crystallization temperature more efficiently than hydrophobic nanosilica. Furthermore, crystallization process of PCL/SAN blends filled with hydrophobic nanosilica was suppressed as the restriction effect of nanosilica on the crystal growth always outweighed their heterogeneous nucleation effect. In contrast, low content of hydrophilic nanosilica (≤1 wt %) were more likely to exhibit growth restriction effect rather than nucleation effect, whereas heterogeneous nucleation effect of higher content of hydrophilic nanosilica (>1 wt %) dominated over growth restriction effect on facilitating the crystallization behavior. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44157.     

Silver‐releasing and antibacterial activities of polyphenol‐based polyurethanes

Inspired by mussel adhesive proteins, catechol functional groups play an important role in the ability of the mussel to adhere to organic and inorganic surfaces. A novel functional polyurethane (PU) based on hydrolysable tannins that contain a number of catechol groups was successfully synthesized and characterized. These catechol groups were used as a reducer for Ag (I) to form Ag (0), and to prepare polyurethane/silver nanoparticles composites. These kinds of polyurethane containing Ag nanoparticles showed obvious inhibition of bacterial growth because of the conjunct actions of the well‐known antibacterial property of silver and the antifouling property of PEG. It is possible for these materials to be applied widely into antibacterial adhesive coatings for surface modification due to their low cost and the material‐independent adhesive property of catechol groups in tannins. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41349.