Tensile Strength Of Composite Films Research Articles

Polyarylene ether nitrile/divinyl siloxane‐bisbenzocyclobutene composite films: Curing reaction and thermal/mechanical/dielectric properties

AbstractPolymer dielectrics, are commonly used as insulating materials for electronic products. Light weight, good mechanical properties and high thermal conductivity are important properties. However, electrical and thermal parameters are interrelated, and it is challenging to have a dielectric polymer that is also resistant to high temperatures and high thermal conductivity. Hence, high‐performance composite films were prepared by the method of post‐solid phase chemical reaction using polyarylene ether nitrile (PEN) and divinyl siloxane‐bisbenzocyclobutene (BCB) as raw materials. First, parameters of the curing reaction were determined by rheological and activation energy calculations. Then, through adjusting the content of BCB resin and treatment temperature, the performance of PEN/BCB composites could be tuned. Thermal properties have been studied by differential scanning calorimetry, dynamic mechanical analysis, thermal gravimetric analysis, and hot‐disk method. Here, the PEN/BCB composite electric insulating materials with outstanding thermal performance (Tg: 208–400°C, T5%: 469–544°C, thermal conductivity: 1.270–2.215 W/m K). Besides, its mechanical and dielectric properties were investigated in detail. It is noteworthy that the tensile strength of composite film can exceed a maximum of 130 MPa, which is 23.19% higher compared to the untreated one. Also, PEN/BCB composites own low dielectric constant (2.27–4.08 at 1 KHz), and the relationship between frequency or a wide temperature range and dielectric constant/loss is stable. Thus, it has a greater potential for applications in electronics in high‐temperature environments.

Preparation of Anti-Bacterial Cellulose Nanofibrils (CNFs) from Bamboo Pulp in a Reactable Citric Acid-Choline Chloride Deep Eutectic Solvent.

In this study, bamboo pulp was simultaneously fibrillated and esterified in one-pot citric acid-choline chloride deep eutectic solvent treatment. The results indicated that increasing the temperature and time promoted esterification, yielding 0.19 to 0.35 mmol/g of the carboxyl group in CNFs. However, increasing the temperature and time resulted in decreases in yields and the diameter of CNFs from 84.5 to 66.6% and 12 to 4 nm, respectively. Analysis of the anti-bacterial activities of CNFs suggested that the high carboxyl group content corresponded to the effective inhibition of Escherichia coli and Staphylococcus aureus Taking yield, size, carboxyl group content, and anti-bacterial activate into consideration, treatment at 120 °C for 24 h was the optimal condition, yielding 76.0% CNF with 0.31 mmol/g carboxyl groups with a diameter of 8 nm and the inhibition fof E. coli (81.7%) and S. aureus (63.1%). In addition, effect of different CNFs on characteristics of polyvinyl alcohol (PVA) films were investigated. The results indicated that CNF obtained from the optimal condition was a favorable additive for the composite film, which enhanced (74%) the tensile strength of composite film compared with the pure PVA film due to its considerable size and carboxyl group content. However, the composite films did not show an anti-bacterial activate as CNF.

Preparation and characterization of citric acid crosslinked chitosan‐cellulose nanofibrils composite films for packaging applications

AbstractThe inferior water vapor permeability and water resistance properties are the major challenges that hindered the development of chitosan‐CNF composites for packaging applications. In this study, the chitosan‐CNF composite films were prepared with in situ crosslinking of citric acid (CA) to reduce the percent water uptake (WU) and water vapor permeability (WVP). The composite films were produced by the solvent casting method with 10%, 15%, and 20% CNF as a reinforcement, 20%, 25%, and 30% CA as a crosslinker, and 20% glycerol as a plasticizer. The Fourier transform infrared (FTIR) spectra of composite films with a peak at 1710 cm−1 confirmed the effective crosslinking of citric acid on the chitosan‐CNF matrix. The crosslinked composite films exhibited the lowest WU of 39% and WVP of 9.99 × 10−7 g/Pa s m2 with reduced light transmittance due to CNF reinforcement. The scanning electron microscopy (SEM) study showed the smooth surface morphology of composite films. The CA crosslinking slightly decreased the tensile strength of composite films. However, the composite film with optimal CNF and CA concentration (25% and 20%, respectively) exhibited comparable tensile strength with other synthetic and biopolymer composites and can be used as a potential biopolymer composite for packaging applications.

Physicochemical and antimicrobial properties of chitosan composite films incorporated with glycerol monolaurate and nano-TiO2

Antimicrobial composite films for active food packaging were developed based on chitosan, glycerol monolaurate (GML), and nano-TiO2. The rheological, morphological, physical, and antimicrobial properties of chitosan-based composite films doped with GML and nano-TiO2 were investigated. All film-forming solutions showed typical pseudoplastic properties, and the viscosity of film-forming solutions increased after the addition of GML. The chitosan films incorporated with GML were transparent, and the transparency of films decreased after adding nano-TiO2. The chitosan-TiO2 composite film containing 1.5% GML exhibited the highest UV–vis barrier properties. Scanning electron microscopy images showed that the surface of films containing GML presented a rough structure, and the changes in the microstructure of films were also confirmed by the results obtained using atomic force microscopy. The addition of GML and nano-TiO2 improved the water-resistance and the barrier properties of the chitosan film. Increasing the GML content resulted in increased water contact angle and decreased the permeability of water vapor, oxygen, and carbon dioxide of composite films. Moreover, the incorporation of GML reduced the tensile strength of composite films. Fourier transform infrared spectroscopy and X-ray diffraction indicated that the interaction among chitosan, GML, and nano-TiO2 could be established through non-covalent bonds. Notably, chitosan-based composite films doped with GML and nano-TiO2 exhibited strong antimicrobial activity, and the film containing 1.5% GML was the most effective. The structure of bacterial cells was injured by the composite films. Overall, the developed composite films exhibited excellent functional properties and could be potential targets for bioactive packaging.

Fabrication and testing of low-cost and flexible smart sensors based on conductive PEDOT-PSS nanocomposite films for the detection of liquefied petroleum gas (LPG) at room temperature

Owing to their high potential applications, the organic conductive layers and devices on flexible substrates as gas sensors at room temperature have been receiving increasing attention. Hence, there is a continued need to develop novel gas sensing materials with excellent mechanical, electrical and sensing stability along with mechanical flexibility in comparison to conventional metal oxide based materials. In this work, we present fabrication of a novel nano-heterojunction between poly (3, 4-ethylenedioxythiophene: poly (styrene sulfonic acid)) (p-PEDOT-PSS) and Tin oxide (n-SnO2) treated with Dimethyl sulfoxide (DMSO) and poly (vinyl alcohol) using a simple spin coating technique. The surface morphology and distribution of SnO2 nanoparticles in the composite was investigated through SEM, whereas the structural features of the composite and bare PEDOT-PSS were compared through XRD. The post treatment of the composite film with strong acid (H2SO4) enhances the conductivity by several orders of magnitude. Presence of DMSO and PVA substantially improves the Young's modulus and Tensile strength of composite films. This ultra-sensitive, highly flexible thin layer of PEDOT-PSS: DMSO: PVA SnO2 composite film post-treated with H2SO4 was employed as a chemiresistive sensor towards detection of LPG (10–100 ppm) at room temperature. The composite sensor shows excellent sensitivity of 79% @ 100 ppm of LPG with long term stability, short response and recovery time of 25s and 30s respectively. This work reports for the first time, LPG gas sensor at room temperature with highly stable sensitivity at various bending angles and exposure to different humidity conditions (0–100% RH). Due to excellent conductivity, sensitivity, short response/recovery time, stability under mechanical deformations and humidity conditions, these composites can be ideal materials to be used as flexible sensors towards detecting LPG at room temperature.

Fabrication of anti-bacterial, hydrophobic and UV resistant galactomannan-zinc oxide nanocomposite films

The use of organic and inorganic materials to prepare membrane materials with functional performance has attracted much attention in recent years. In this paper, galactomannan (GM) is used as raw material and nano zinc oxide (nano-ZnO) is used as functional modifier to prepare GM based food packaging films. The properties influence for films of different nano-ZnO content were studied. The obtained nano-ZnO/GM composite films showed superior hydrophobicity and almost absorbing all UVA and UVB. The tensile strength of composite film was superior to plastic HDPE film, and the oxygen barrier properties of composite films were better than PVC plastic film. The composite films against E. coli and B. subtilis showed great antibacterial properties. The antibacterial effect was demonstrated by Shine-Muscat grapes after storage for 5 days. The final prepared GM based functional food packaging film provides a foundation for the potentials for futural plastic packaging alternatives.

Improving oxygen barrier properties of PET composites via grafting hydroxy‐terminated polybutadiene with nanosilica

Hydroxy‐terminated polybutadiene (HTPB) was grafted onto nanosilica via two steps, and then melt extruded with PET and transition metal catalyst. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) results showed that HTPB successfully bridged to the surface of nanosilica through toluene‐2,4‐diisocyanate (TDI), and the grafting amount of HTPB accounted for about 11.2% of the total mass of nanosilica. The PET composite samples were also uniaxially stretched into films. Tensile results showed that the tensile strength of composite films was generally higher than that of composite sheets, especially the tensile strength of PET/SiO2‐HTPB composite film reached 139.8 MPa. After uniaxial stretching, the crystallinity of all films were significantly improved, and fillers accelerated the crystallization rate of PET, which greatly improved the crystallinity of composite materials, thereby contributing to the improvement of the oxygen barrier performance of composite materials. After adding the catalyst, the PET/SiO2‐HTPB/Co composite film has the lowest oxygen permeability coefficient of 1.05 × 10−15 (cm3·cm/cm2·s·pa), which was 87.6% lower than that of pure PET sheet. SEM showed that the compatibility between filler and matrix was improved. This study demonstrated that nanosilica grafted with HTPB played a synergistic role in improving the crystallinity of materials and exerting the active oxygen scavenging of HTPB, and uniaxial stretching was helpful for improving the comprehensive properties of composites.

Nanoarchitectonics Composites of Thermoplastic Starch and Montmorillonite Modified with Low Molecular Weight Polylactic Acid.

Nano montmorillonite (MMT) was modified by low molecular weight polylactic acid (PLA), then, the PLA modified MMT and raw MMT were added into thermoplastic starch (TPS) to prepare biodegradable nanocomposite films, respectively. For both nanocomposite films with raw MMT and modified MMT, the Tmax of degradation was enhanced and the mechanical properties were improved. The composite films containing 4 wt.% MMT displayed tensile strength of 5.06 MPa, approximately 1.4 times of that for the pure TPS films. The tensile strength of composite films containing 4 wt.% modified MMT is 6.74 MPa approximately 2 times of those for pure starch films. On the other hand, the composite film containing 4 wt.% modified MMT displayed elongation at break as high as 34.25%, which is 1.3 times of that of the pure starch film, while the composite films containing raw MMT had reduced elongation at break. This study showed that the MMT modified with PLA could significantly enhance the mechanical properties of TPS, and provides a new method to prepare fully biodegradable starch-based nanocomposites.

Chitin nanocrystals reticulated self‐assembled architecture reinforces deproteinized natural rubber latex film

AbstractNatural rubber (NR) latex was initially deproteinized, then, the interactions between chitin nanocrystals (ChNCs) and deproteinized natural rubber (DNR) latex particles in an aqueous system and the properties of DNR/ChNCs composites were investigated. Composite films were obtained by casting and evaporating off the prevulcanized DNR/ChNCs complexation rather than simply mixing of DNR latex and ChNCs suspension. The results of DLS and TEM confirmed that this kind of complexation was formed between negative charged DNR and positively charged ChNCs by self‐assembly. The tensile strength of composite films containing 4 wt% ChNCs was 25.00 ± 1.42 MPa, which was 3.11 multiples of the pure pre‐vulcanized DNR. DNR/ChNCs composite films could provide excellent mechanical properties and avoid allergies caused by proteins in NR latex.

Mechanical properties and thermal stability of porous polyimide/hollow mesoporous silica nanoparticles composite films prepared by using polystyrene microspheres as the pore‐forming template

ABSTRACTThe porous polyimide/hollow mesoporous silica nanoparticles (PI/HMSNs) composite films were fabricated via blending polymerization by using polystyrene (PS) microspheres as the pore‐forming template. The morphologies, microstructures, thermal stability, thermal expansion coefficient (TEC), and mechanical performances of the porous PI/HMSNs films were characterized in detail. Results showed that the uniform dispersion of HMSNs benefits from the strong hydrogen‐bonding interaction between the hydroxyl groups of HMSNs and poly(amic acid) chains. Both weight loss and TEC of the porous PI/HMSNs films are lower than those of the pure porous PI film. When 0.8 wt % HMSNs and 7.0 wt % PS were added into the PI matrix, the Young's modulus and tensile strength of composite film increased by about 32.4% and 68.1% compared with those of the pure porous PI film. Conclusively, the introduction of HMSNs in the porous PI matrix is an important strategy to enrich the diversity of porous structure, improve the thermal and mechanical properties of the porous PI material simultaneously. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2020,137, 48792.

Dual bond synergy enhancement to mechanical and thermal properties of castor oil-based waterborne polyurethane composites

An environmentally friendly waterborne polyurethane based on castor oil was prepared and modified by 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose microfibers (TOCMF). The TOCMF with surface-attached active carboxyl groups was obtained by TEMPO/NaClO/NaBr system, and then the modified castor oil-based waterborne polyurethane was prepared by the synergistic action of covalent bond and hydrogen bond between TOCMF and prepolymer in the in-situ polymerization reaction. The introduction of carboxylate on the surface of TOCMF facilitated stabilization of the thickness of the double layer of the emulsion particles to form stable WPU/TOCMF dispersions. Benefiting from the filamentous structural effects of TOCMF and the covalent bond and hydrogen bond dual interactions in WPU matrix, WPU/TOCMF composite films showed improvement in tensile strength and thermal decomposition temperature. Tensile strength of composite films increased from 17.89 to 30.31 MPa with increasing TOCMF amount from 0 to 1.00 wt%. T5% of composite films increased from 202.6 to 239.3 °C with increasing TOCMF amount from 0 to 0.75 wt%. It was observed by SEM that the presence of agglomeration in the composite film with 1.25 and 1.50 wt% TOCMF, and the occurrence of agglomeration caused the performance of the composite film to deteriorate sharply.

Oxidized microcrystalline cellulose improve thermoplastic starch-based composite films: Thermal, mechanical and water-solubility properties

The pursuit of sustainable plastic packaging materials stimulates the development of new materials based on renewable resources and efficient fabrication methods. In this study, thermoplastic hydroxypropyl starch (TPS) as a matrix and oxidized microcrystalline cellulose (MCC) as a reinforcing agent were used to prepare water-soluble composite films via a hot-compression molding technique. As-prepared composite films were disintegrated in water in approximately 60 s, which could potentially reduce plastic pollution in the environment. In addition, MCC was treated to enhance the tensile strength of composite films, with a remarkable increase of ∼249.42%. The composite films are composed of renewable, biodegradable, and environment-friendly materials, and the fabrication process is environmentally benign, highly efficient, cost-effective, and easy for scaling up. The new composite films can be used as a renewable water-soluble material for industrial applications.

Mechanical properties of whey protein concentrate based film improved by the coexistence of nanocrystalline cellulose and transglutaminase

Whey Protein Concentrate (WPC) has been researched as food packaging materials in recent years. However, WPC films own the drawbacks on the barrier ability to water vapor and mechanical properties. In the presented work, Transglutaminase (TGase) and different concentrations of nanocrystalline cellulose (NCC) (0–15% wt. of WPC) were incorporated into the WPC matrix to prepare WPC-NCC composite film, their transmittance, mechanical properties, water vapor permeability and microstructures were investigated and compared with that of WPC films. Results illustrated that NCC as fillers in the protein network blended with WPC markedly improved the mechanical properties. The tensile strength of composite film increased from 1.3 to 3.15 MPa as NCC increased to 15% wt. of WPC. Moreover, TGase took a promoted effect on mechanical properties. The composite film achieved a maximal elongation value of 86.7% when TGase was added at 9 U/g of WPC. SDS-PAGE confirmed that TGase positively facilitated the formation of the protein polymers. FTIR analysis observed conformational changes caused by TGase in the films and implied the interaction between WPC and NCC. Results suggest NCC and TGase have a synergy effect on mechanical properties of WPC based film, and TGase-crosslinked WPC-NCC composite film can be applied as an alternative packaging material.

Composite Film Based on Pulping Industry Waste and Chitosan for Food Packaging.

Wood auto-hydrolysates (WAH) are obtained in the pulping process by the hydrothermal extraction, which contains lots of hemicelluloses and slight lignin. WAH and chitosan (CS) were introduced into this study to construct WAH-based films by the casting method. The FT-IR results revealed the crosslinking interaction between WAH and CS due to the Millard reaction. The morphology, transmittance, thermal properties and mechanical properties of composite WAH/CS films were investigated. As the results showed, the tensile strength, light transmittances and thermal stability of the WAH-based composite films increased with the increment of WAH/CS content ratio. In addition, the results of oxygen transfer rate (OTR) and water vapor permeability (WVP) suggested that the OTR and WVP values of the films decreased due to the addition of CS. The maximum value of tensile strengths of the composite films achieved 71.2 MPa and the OTR of the films was low as 0.16 cm3·μm·m−2·24 h−1·kPa−1, these properties are better than those of other hemicelluloses composite films. These results suggested that the barrier composite films based on WAH and CS will become attractive in the food packaging application for great mechanical properties, good transmittance and low oxygen transfer rate.

Preparation of polyethylene glycol diglycidyl ether (PEDGE) crosslinked chitosan/activated carbon composite film for Cd2+ removal

Preparation and characterization of polyethylene glycol diglycidyl ether (PEDGE) crosslinked chitosan/activated carbon composite film have been conducted. PEDGE was used as crosslinking agent and activated carbon as a filler on composite film preparation. The composite films were produced with several ratios of chitosan/PEDGE/activated carbon. Tensile test, Fourier Transform Infrared (FTIR), X-Ray Diffraction (XRD) and Scanning electron Microscope (SEM) were used to study the structure and properties of PEDGE crosslinked chitosan/activated carbon composite film. Tensile test results showed crosslinking and filler influenced the tensile strength of composite films. The best composite film was obtained at 0.70/0.10/0.20 mixing ratio of chitosan/PEDGE/activated carbon. FTIR, SEM and XRD analysis confirmed the formation of PEDGE crosslinked chitosan/activated carbon composite films. The obtained PEDGE crosslinked chitosan/activated carbon composite film was used for adsorption of Cd2+. The highest adsorption capacity of Cd2+ was obtained at pH 5 and 40 min contact time. Based on Langmuir adsorption isotherm model, the maximum adsorption capacity (Q) of Cd2+ by PEDGE crosslinked chitosan/activated carbon composite film was 357.14 mg/g. Regeneration studies showed the PEDGE crosslinked chitosan/activated carbon composite film can be used repeatly with high performance.

Process optimization of ultrasound-assisted treatment for soya bean protein isolate/polyacrylamide composite film.

In this paper, composite films composed of soya bean protein isolate (SPI) and polyacrylamide (PAM) were prepared under variations of ultrasonic power, treatment time and heating temperature. The effects of the major processing parameters related to ultrasonic-assisted treatment were evaluated and optimized through the single-factor analysis and Box–Behnken design (BBD), respectively, when the tensile strength of composite films was considered as the response value. The single-factor analysis was carried out to study the effects of ultrasonic power, treatment time and heating temperature on the viscosity and cohesion of the slurry and the tensile strength of SPI/PAM composite films, which also provided a reasonable data range of each factor for further optimization. Experiment results indicated that these three factors play a significant role in the tensile strength of films. Then BBD was applied to optimize the treatment conditions of these three factors, using the tensile strength of films as the response value. According to the interactive second-order polynomial model of three factors and the three-dimensional response surface, the maximum tensile strength of films was obtained under the optimal condition. To verify the reliability of the model, the experiment with the optimal condition was conducted, and results demonstrated that the observed tensile strength was in agreement with the predicated one. Also, the morphology and water solubility of the films showed that the film can be coated on the yarns evenly and removed clearly.

Fabrication of a piezoelectric polyvinylidene fluoride/carbonyl iron (PVDF/CI) magnetic composite film towards the magnetic field and deformation bi-sensor

In this paper, a versatile polyvinylidene fluoride/carbonyl iron (PVDF/CI) composite film was prepared by doping magnetic carbonyl iron (CI) particles into piezoelectric polyvinylidene fluoride (PVDF) matrix. Without influencing the piezoelectric structure of PVDF, CI particles enhanced the Young's modulus and maximum tensile strength of composite films. Due to the magnetic driven characteristic, PVDF/CI composite films exhibited distinct magnetic-mechanic-electric coupling properties. The piezoelectric charge signals could be generated by applying the bending deformation or magnetic field. Taking PVDF/CI-10% (CI content was 10 wt%) film as an example, the piezoelectric charges under 2, 4, 6, 8, and 10 mm bending displacement were 3.0, 9.6, 14.9, 18.6, and 24.6 pC respectively. Moreover, when the magnetic field varied from 0 to 600 mT, the generated magneto-electric charges of PVDF/CI-10% film increased from 0 to 676 pC. The quantitative relationship between magnetic field and magneto-electric charges was obtained by the polynomial fitting method and the correlation coefficient was up to 0.97. Owing to the ideal piezoelectricity, excellent stability, light weight and desirable flexibility, PVDF/CI composite films showed promising applications in deformation sensor and magnetic field sensor.

Investigation of structural and thermal properties of distinct nanofillers-doped PVA composite films

Purpose of present study was to investigate the effect of different nanofillers doping on structural and thermal properties of poly(vinyl alcohol) (PVA)-based nanocomposite films. Herein, ZnO nanoparticles (NPs), CuO NPs, graphene oxide and reduced graphene oxide (RGO) nanosheets have been used as separate nanofillers in the formation of PVA nanocomposite films via solution casting approach. The prepared composite films were characterized using X-ray diffraction, scanning electron microscopy, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, differential scanning calorimetry and tensile strength testing. The results demonstrate the effect of various nanofillers on glass transition temperature (Tg), melting temperature (Tm), crystallization temperature (Tc), percentage crystallinity (%χc) and tensile strength of composite films. A doping with (0.02 wt%) RGO nanosheets caused significant influence on thermal properties and tensile strength of PVA composite films as compared to other test nanofillers. The doping with RGO nanosheets resulted in elevation of Tg (48.2 °C), Tm (218.3 °C), Tc (157.8 °C) and %χc (41.9%) as compared to that of pure PVA (Tg 38.4 °C, Tm 190.4 °C, Tc 115.1 °C and %χc 22.2%). Overall, the doping of PVA with graphene-based nanosheets exhibited better tensile strength and thermal stability of nanocomposite as compared with other tested nanofillers.

Electrically Conductive Graphene-Based Biodegradable Polymer Composite Films with High Thermal Stability and Flexibility

Cellulose nanofibril (CNF) and graphene (GR) powder were added into polylactic acid (PLA)/polypyrrole (PPy) composite films via a low-cost, eco-friendly, low-temperature, and in-situ polymerization synthesis, which obtain novel flexible and conductive polylacticacid-cellulose nanofibril-graphene/polypyrrole (PLA–CNF–GR/PPy) composite films. The CNF was embedded in the PLA matrix to enhance the mechanical properties. Remarkably, when a few GR (1%) powder was added, the tensile strength of composite films increased by 5.6%, respectively, compared with pure PLA–CNF, and increased by 17.6% compared with the PLA. The GR and CNF had a positive influence on mechanical properties of composite films. In addition, the PLA–CNF–GR/PPy composite films exhibited many unique properties when GR powder was introduced, including high thermal stability, and especially electrical conductivity. The electrical conductivity of the PLA–CNF–GR/PPy composite films increased from 0.12 to 1.06[Formula: see text]S/cm as the content of GR powder increased from 0 to 10%. The PLA–CNF–GR-10/PPy also demonstrated excellent flexible stability, only 7.5% deviation after over 100 bending cycles. Furthermore, we designed and found that the exploration of a flexible solid-state supercapacitor assembled with PLA–CNF–GR-10/PPy composite electrodes had a capacitance of 30[Formula: see text]F/g at a current density of 0.5[Formula: see text]A/g. Although it was not quite as prominent as the capacitance, it provided an innovative means for preparing the conductive composite films. Based on these advantages the PLA–CNF–GR/PPy could be considered as sensors, flexible electrodes, and flexible displays. It also opens a new field of potential applications of biodegradable materials.

Antibacterial membranes based on chitosan and quaternary ammonium salts modified nanocrystalline cellulose

Etherification of nanocrystalline cellulose (NCC) with three kinds of quaternary ammonium salts epoxypropyltrimethylammonium chloride, N,N‐dimethyl‐N‐dodecyl‐N‐(1,2‐epoxypropyl) ammonium chloride (DMDEPAC), and N,N‐dimethyl‐N‐octadecyl‐N‐(1,2‐epoxypropyl) ammonium chloride (DMOEPAC) was successfully performed via a nucleophilic addition reaction. The synthesized DMDEPAC and DMOEPAC were characterized by nuclear magnetic resonance. The modified NCC particles, NCC epoxypropyltrimethylammonium chloride, NCC‐DMDEPAC, and NCC‐DMOEPAC, were characterized by energy dispersive spectrometer. Nanocomposite films based on chitosan (CS) containing quaternary ammonium salts modified NCC were prepared with nanoparticle loadings of 5.0, 7.5, and 10.0%, respectively. The effect of nanoparticle content on the tensile strength of composite films was studied. The results indicated that the films with 5.0% nanoparticle loading exhibited the biggest increase in tensile strength. Surface morphology, smoothness, and antibacterial properties of composite films containing 5% modified NCC were also studied. CS/NCC‐DMDEPAC‐5.0 and CS/NCC‐DMOEPAC‐5.0 displayed excellent biocidal abilities against both Gram‐positive Staphylococcus aureus (ATCC 6538) and Gram‐negative Escherichia coli O157:H7 (ATCC 43895). The bio‐based nanocomposite films with increased mechanical strength and excellent antibacterial properties show great potential as food packaging materials. Copyright © 2017 John Wiley & Sons, Ltd.