Valorization of pineapple peel waste and sisal fiber: Study of cellulose nanocrystals on polypropylene nanocomposites

The present study focuses on the isolation and characterization of the cellulose nanocrystals (CNCs) from the pineapple peel waste (PPW) (agro-waste) and sisal fiber (SiF) (natural fiber) employing the acid hydrolysis method, and its comparison with the commercially available CNCs (CNC-C). Furthermore, the CNCs from PPW, SiF, and CNC-C were subjected to transmission electron microscopy (TEM), Fourier transform electron microscopy, X-ray diffraction, particle size distribution, and zeta potential analysis. The studied properties of the isolated CNCs are considerably different from the PPW and SiF. The CNCs so formed have been estimated by TEM to be around 10–40 nm wide and length of several micrometers. Fourier transform electron microscopy studies described the removal of the noncellulosic components like lignin, hemicellulose, and pectin substances from the base materials in both the cases by employing acid hydrolysis method. Additionally, nanocomposites of CNC isolated from PPW along with polypropylene (PP) matrix were fabricated using melt blending method followed by injection molding. Maleic anhydride grafted PP (MAPP) acts as a compatibilizer for improving the dispersibility of hydrophilic CNC within the nonpolar PP matrix. The addition of CNC (3 wt%) along with MAPP at 5 wt% showed optimum tensile strength and modulus to the tune of 10.39 and 25.53%, respectively, when compared to their counterparts without MAPP. Dynamic mechanical analysis revealed an increased stiffness of PP in its nanocomposite system due to the addition of CNC. Scanning electron microscopy studies revealed uniform distribution of CNC within the nonpolar PP matrix in the presence of MAPP.     

Surface modification and antimicrobial properties of cellulose nanocrystals

A novel and simple surface modification of cellulose nanocrystals (CNC) was performed by chloroacetylation and subsequent reaction with tertiary amines to form quaternary ammonium modified CNCs. The acetylation of CNC and quaternary ammonium modified CNCs was confirmed using IR spectroscopy and solid state NMR spectroscopy. The ¹³C NMR spectrum of quaternary ammonium modified CNC showed several additional resonances ranging from 14.5 ppm to 58.0 ppm compared to ¹³C NMR spectrum of pure CNC, suggesting that alkyl chains have been added to the pure CNC. The disc diffusion method was used to evaluate the antimicrobial properties of quaternary ammonium modified CNCs. It was found that modified CNCs with alkyl chain longer than ten carbons are effective antimicrobial agents against Staphylococcus aureus and E. coli bacteria. These CNCs can be chemically modified to tailor the properties to improve dispersion in the polymer matrix. This will expand the application of CNC as a reinforcing material. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44789.     

Morphological,thermal, and mechanical properties of poly(ε‐caprolactone)/poly(ε‐caprolactone)‐grafted‐cellulose nanocrystals mats produced by electrospinning

Electrospun nanocomposites of poly(ε‐caprolactone) (PCL) incorporated with PCL‐grafted cellulose nanocrystals (PCL‐g‐CNC) were produced. PCL chains were grafted from cellulose nanocrystals (CNC) surface by ring‐opening polymerization. Grafting was confirmed by infrared spectroscopy (FTIR) and thermogravimetric analyses (TGA). The resulting PCL‐g‐CNC were then incorporated into a PCL matrix at various loadings. Homogeneous nanofibers with average diameter decreasing with the addition of PCL‐g‐CNC were observed by scanning electron microscopy (SEM). PCL‐g‐CNC domains incorporated into the PCL matrix were visualized by transmission electron microscopy (TEM). Thermal and mechanical properties of the mats were analyzed by differential scanning calorimetry (DSC), TGA and dynamic mechanical analysis (DMA). The addition of PCL‐g‐CNC into the PCL matrix caused changes in the thermal behavior and crystallinity of the electrospun fibers. Significant improvements in Young's modulus and in strain at break with increasing PCL‐g‐CNC loadings were found. These results highlighted the great potential of cellulose nanocrystals as a reinforcement phase in electrospun PCL mats, which can be used as biomedical materials. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43445.     

Spider Silk-CBD-Cellulose Nanocrystal Composites: Mechanism of Assembly

The fabrication of cellulose-spider silk bio-nanocomposites comprised of cellulose nanocrystals (CNCs) and recombinant spider silk protein fused to a cellulose binding domain (CBD) is described. Silk-CBD successfully binds cellulose, and unlike recombinant silk alone, silk-CBD self-assembles into microfibrils even in the absence of CNCs. Silk-CBD-CNC composite sponges and films show changes in internal structure and CNC alignment related to the addition of silk-CBD. The silk-CBD sponges exhibit improved thermal and structural characteristics in comparison to control recombinant spider silk sponges. The glass transition temperature (Tg) of the silk-CBD sponge was higher than the control silk sponge and similar to native dragline spider silk fibers. Gel filtration analysis, dynamic light scattering (DLS), small angle X-ray scattering (SAXS) and cryo-transmission electron microscopy (TEM) indicated that silk-CBD, but not the recombinant silk control, formed a nematic liquid crystalline phase similar to that observed in native spider silk during the silk spinning process. Silk-CBD microfibrils spontaneously formed in solution upon ultrasonication. We suggest a model for silk-CBD assembly that implicates CBD in the central role of driving the dimerization of spider silk monomers, a process essential to the molecular assembly of spider-silk nanofibers and silk-CNC composites.     

磷酸锆辅助催化水解菌糠制备纳米纤维素晶体的性能

以食用菌产业的副产品菌糠为原料,采用磷酸锆催化剂辅助稀硫酸水解制备纳米纤维素晶体(cellulose nanocrystals,CNCs).与传统酸水解方法相比,该方法简化了工艺流程,制备过程环境友好。考察了超声时间、超声温度以及稀硫酸浓度等因素对CNCs得率的影响。结果表明当超声时间为5h、超声温度为75℃及稀硫酸浓度为12.3%时,CNCs得率为42.80%.采用透射电子显微镜(TEM)、扫描电子显微镜(SEM)、傅里叶变换红外光谱(FTIR)以及X射线衍射仪(XRD)对样品的微观形貌、谱学性能和晶体结构进行了研究分析,结果表明所制得的CNCs呈棒状,直径介于10～30nm之间;CNCs属于纤维素I型,与原料菌糠相比,结晶度由63.79%增大到81.04%;且CNCs仍具有天然纤维素的基本化学结构。论文研究为菌糠的资源化高效利用开辟了新途径。     

Office waste paper as cellulose nanocrystal source

Cellulose nanocrystals (CNC) are isolated from office waste paper using an alkali solution and a subsequent acid hydrolysis process. The Fourier transform infrared spectroscopy and X‐ray diffraction (XRD) results demonstrate that ink and fillers used in the papermaking industry are almost totally removed after alkali treatments. The XRD results show that CNCs obtained after 2 wt % NaOH solution treatment and a subsequent hydrolysis process exhibit only a cellulose I crystalline structure, and the crystallinity index value increases around 42% with respect to initial office waste paper. Nevertheless, CNCs obtained after 7.5 wt % NaOH solution treatment and a subsequent acid hydrolysis process show a mixture of cellulose I and cellulose II polymorphs. The thermal analysis shows that the CNCs obtained after 7.5 wt % NaOH solution treatment and a subsequent acid hydrolysis process are thermally less stable than other samples, suggesting that the cellulose chains could depolymerize into low molecular weight sugar compounds. Even though the atomic force microscopy images confirm the presence of CNCs, the optical images show that some cellulose microfibers still maintain their structure. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45257.     

Analyzing three‐dimensional structure and geometrical shape of individual cellulose nanocrystal from switchgrass

The three‐dimensional morphology, size distribution, and structure of individual cellulose nanocrystals (CNCs) isolated from switchgrass (Panicumvirgatum L), a representative raw biomass material, were investigated in this research. Width and height evolutions along the individual CNC longitudinal direction were statistically and quantitatively characterized using transmission electron microscopy (TEM) and atomic force microscopy (AFM). Lognormal distribution was identified as the most likely for cellulose nanocrystals’ size distribution. Height and width dimensions were shown to decrease toward the ends from the midpoint of individual CNCs, implying a spindle shape. The observed rough surfaces of CNCs were explainable as the results of acid etching of the subcrystalline and disordered region located at the surface. X‐ray diffraction analysis of crystallite size accompanied with TEM and AFM measurements revealed that the cross‐sectional dimensions of individual switchgrass CNC were either rectangularly or elliptically shaped, with an approximately 3–5 nm lateral element length range. POLYM. COMPOS., 38:2368–2377, 2017. © 2015 Society of Plastics Engineers     

Simple preparation of long-persistent luminescent paint with superhydrophobic anticorrosion efficiency from cellulose nanocrystals and an acrylic emulsion

Novel photoluminescent paint was prepared for safety marking purposes using an emulsion system composed of an acrylic polymer, cellulose nanocrystals and lanthanide-doped strontium aluminate (LdSA) nanopaticles. The effect of LdSA concentration in the paint formula was investigated. Cellulose nanocrystals (CNCs) have been an attractive reinforcement material that can be incorporated into protective coatings due to their distinctive properties, such as biocompatibility, biodegradability, and renewability. The produced acrylic/cellulose nanocrystals/lanthanide-doped strontium aluminate paints were applied onto different surfaces of asphalt concrete and tinplate panels. LdSA was developed in the nano-scale form as described by transmission electron microscope (TEM) to allow a better dispersion in the paint formula. The applied paints were studied by energy-dispersive X-ray spectroscopy (EDS), X-ray fluorescence (XRF), scan electron microscopy (SEM), and infrared spectra (FTIR). Both transparency and coloration measurements of the applied paints were investigated by luminescence spectra and CIE Lab. The resistance to scratching, hydrophobic and corrosion resistivity were investigated. CNCs were monitored to be a key component for the anti-corrosion activity. The best long-lived luminescence was monitored for more that 60 min in the dark for LdSA concentration of 12% w/w. The paints containing cellulose nanocrystals and sodium hexametaphosphate demonstrated satisfactory results upon mixing with acrylic emulsion.     

Microstructural,Thermal, Crystallization,and Water Absorption Properties of Films Prepared from Never-Dried and Freeze-Dried Cellulose Nanocrystals

In this paper, the microstructural, optical, thermal, crystallization, and water absorption properties of films prepared from never-dried (ND) and freeze-dried (FD) cellulose nanocrystals (CNCs) are reported. Morphology of the ND CNCs reveals a needle-like structure, while after freeze-drying, they show a flake-like morphology. Microstructural analysis of ND and FD CNCs are further studied via small angle X-ray scattering to probe interactions. ND CNCs yield a transparent film with a low surface roughness (14 ± 4 nm), while the FD CNC film evidence a significant reduction of their transparency due to their higher surface roughness (134 ± 20 nm). Although Fourier transform infrared spectroscopy and energy-dispersive X-ray spectroscopy analyses reveal no chemical change occurs during the freeze-drying process, yet a more intense thermal degradation profile is observed for FD CNC film, probably due to the higher oxygen ingress within the gaps created between the stacked flakes. This, in turn, results in a greater loss of crystallinity at a higher temperature (300 °C) compared to the ND CNC film. A rapid decrease in water contact angle of the FD CNC film proves that the morphology of flakes and their orientation within the film has a strong influence in increasing water absorption capacity.     

Crosslinked PVA nanofibers reinforced with cellulose nanocrystals: Water interactions and thermomechanical properties

Acid‐catalyzed vapor phase esterification with maleic anhydride was used to improve the integrity and thermo‐mechanical properties of fiber webs based on poly(vinyl alcohol), PVA. The fibers were produced by electrospinning PVA from aqueous dispersions containing cellulose nanocrystals (CNCs). The effect of esterification and CNC loading on the structure and solvent resistance of the electrospun fibers was investigated. Chemical characterization of the fibers (FTIR, NMR) indicated the formation of ester bonds between hydroxyl groups belonging to neighboring molecules. Thermomechanical properties after chemical modification were analyzed using thermal gravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis. An 80% improvement in the ultimate strength was achieved for CNC‐loaded, crosslinked PVA fiber webs measured at 90% air relative humidity. Besides the ultra‐high surface area, the composite PVA fiber webs were water resistant and presented excellent mechanical properties. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40334.     

Cellulose nanocrystals (CNCs) reinforced acrylic pressure- sensitive adhesives (PSAs) prepared via miniemulsion polymerization

In this study, poly (n-butyl acrylate-co-2-ethyl hexyl acrylate) (P(nBA-co-2EHA)) pressure sensitive adhesives (PSAs) were successfully synthesized in the presence of cellulose nanocrystals (CNCs) via in-situ miniemulsion polymerization. First, the CNCs were prepared via acid hydrolysis of cellulose microcrystals (CMCs) at various temperatures, 42–54 °C, and characterized using atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) apparatus. The results showed that hydrolysis of MCCs at 45 °C resulted in CNCs with a well-defined aspect ratio, average length of 206 nm and thickness of 3.9 nm, and the highest crystallinity. Adding further CNC to the copolymer adhesive enhanced the mean particle size of the composite latex and decreased the glass-rubber transition temperature (T_g) of the copolymer matrix. Molecular weights and viscoelastic properties of the resultant PSAs were determined using gel permeation chromatography (GPC) and dynamic mechanical thermal analysis (DMTA), respectively. Adhesion performance of the neat and reinforced PSAs containing 1–5 wt% CNCs was evaluated at room temperature. The results showed that the incorporation of CNCs up to 4 wt% in the copolymer adhesive increased the shear resistance by 518%, peel strength by 176% and probe tack by 13%, while further addition, 5 wt%, lowered the adhesion performance due to a lack of surface wettability.     

过硫酸铵氧化速生杨木残渣制备纤维素纳米晶体及其表征

以去除半纤维素的速生杨木残渣为原料,在70℃下按固液比1：100（g：mL）加入1.5 mol/L过硫酸铵溶液,处理16 h制备纤维素纳米晶体。所得样品为白色粉末状固体,得率（以原料中纤维素质量计）为57%,氧化度为0.156,表面电荷为-42.15 mV。采用透射电子显微镜、傅里叶变换红外光谱、X射线衍射、核磁共振等技术对得到的纳米纤维素进行表征。结果表明：过硫酸铵去除了原料中的木质素和残余的少量半纤维素,并有选择地将纤维素C6位置上的伯醇羟基氧化成羧基,纤维素纳米晶体保留了原纤维素的结构特征,结晶度为77%,晶体结构以I_β晶型为主,88.4%的纤维素纳米晶体宽度在10~24 nm之间。     

Thermally activated shape memory behavior of melt‐mixed polyurethane/cellulose nanocrystal composites

Building blocks made from renewable sources attract increasing attention for the design of new polymer systems. Recently, in this particular context, cellulose nanocrystals (CNCs) have gained great interest in both academic research and industry, mainly on account of their ability to reinforce range of polymer matrices and afford nanocomposites with attractive mechanical properties. The limited thermal stability of conventionally produced cellulose nanocrystals (CNCs) has, however, so far limited the range of polymers that could be used as basis for melt‐processed CNC nanocomposites. We herein show that a commercially accessible nanocrystal source, a particular grade of microcrystalline cellulose (MCC), can easily be converted into thermally stable CNCs by ultrasonication in phosphoric acid. A scalable melt‐mixing process was used to produce nanocomposites of these CNCs with a thermoplastic polyurethane (TPU) elastomer. A significant improvement of the room temperature storage modulus from 40 MPa (neat polymer) to 120 MPa (10% w/w CNC) was observed. The introduction of CNCs not only increased the stiffness of the polymer matrix, but also improved the shape memory properties of the nanocomposite. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45033.     

A facile approach for fabricating fluorescent cellulose

Fluorescent cellulose nanocrystals (CNCs) were prepared through a two‐step approach. Reactive amino groups were first introduced onto the CNCs through a silanization reaction with 3‐aminopropyltrimethoxysilane. The fluorescent moieties were then attached onto the cellulose by covalent grafting between the amino groups and 1‐pyrenebutyric acid N‐hydroxy succinimide ester or fluorescein isothiocyanate. The synthesized fluorescent CNCs were investigated and characterized with attenuated total reflectance Fourier transform infrared spectroscopy, ultraviolet–visible absorbance and fluorescence spectroscopy, confocal microscopy, and dynamic light scattering. The same fluorescent functionalization strategy could also be applied to other cellulose materials, such as microcrystalline cellulose and bulky paper sheets. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

基于互穿网络技术构筑的氧化海藻酸钠/纤维素纳米晶/聚丙烯酰胺-明胶复合水凝胶与性能

为了提高海藻酸盐水凝胶的生物应用性,采用互穿网络技术、纤维素纳米晶(CNCs)补强和明胶表面覆积相结合的方法构建了氧化海藻酸盐/纤维素纳米晶/聚丙烯酰胺-明胶 (OSA/CNCs/PAM-GT) 复合水凝胶。通过FT-IR、TGA、 XRD、溶胀性和降解性实验以及细胞相容性测试考察了CNCs含量对OSA/CNCs/PAM-GT复合水凝胶结构和性能的影响。实验结果表明,CNCs能够与基体中的聚合物产生相互作用力。并且随着CNCs含量的增加,OSA/CNCs/PAM-GT 复合水凝胶的孔隙率下降,力学性能提高。而且它们的溶胀性和生物降解性虽然受CNCs含量增加而呈现下降的趋势,但是幅度较小,说明CNCs能够在一定程度上调控复合水凝胶的物化性能。同时,OSA/CNCs/PAM-GT 复合水凝胶展现出较好的细胞粘附、增殖和分化性能。当CNCs的含量在0.5%时,细胞增殖的效果最佳,而CNCs的含量为1.5%时,细胞分化效果最显著。因此,将CNCs掺杂到OSA/PAM互穿网络基体中能够有效地调控其生物性能,使其适用于生物医学领域。     

Crosslinked carboxylated SBR composites reinforced with chitin nanocrystals

This study aims to develop and characterize the nanocomposites using sulfur cross-linked carboxylated styrene-butadiene rubbers (S-xSBR) as the matrix and chitin nanocrystals (CNCs) as nanofillers. The composites’ morphology and properties were examined by light transmittances, fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), X-ray diffraction (XRD), dynamic mechanical analysis (DMA), thermo gravimetric analyzer (TGA), and tensile properties determination. The addition of CNCs has slight effect on transparency of the composite films. FTIR data confirm the interfacial interactions between CNCs and S-xSBR via hydrogen bonds. CNCs are uniformly dispersed in the matrix from SEM result. The addition of CNCs can significantly improve the tensile strength and modulus both in static and dynamic states. The tensile modulus and tensile strength of S-xSBR/CNCs composites with the 4 wt.% CNCs is 62.5 % and 97.6 % higher than that of pure S-xSBR. The storage modulus, glass transition temperature, and the thermal stability of the composites are higher than those of the neat S-xSBR. The mechanical properties of the composite films are water-responsive, as the swollen samples exhibit obviously decreased strength and modulus. The greatest mechanical contrast is shown in the S-xSBR/CNCs composites with 2 wt.% CNCs loading whose tensile modulus decrease from 60.4 to 6.1 MPa after swelling equilibrium. The significant reinforcement effect of CNCs on S-xSBR is attributed to the unique structure of CNCs and the interfacial interactions in the composite.     

Extraction of cellulose nanocrystals and fabrication of high alumina refractory bricks using pencil chips as a waste biomass source

Extraction of “green” cellulose nanocrystals (CNCs) from waste biomass is a sustainable strategy for high valued valorization in the view of socio-economic and environmental issues. Herein, for the first time, waste pencil chips (PC) as a potential source of cellulose, were used for the extraction of CNCs. CNCs were successfully extracted from PC wastes using alkali and bleaching chemical treatments to remove hemicellulose and lignin followed by acid hydrolysis using concentrated sulfuric acid. The products after each step were characterized in terms of crystallinity, chemical structures, thermal properties, and morphologies. The XRD results showed that the crystalline index increased about 16% from PC (75%) to CNCs (91%). The FTIR analysis confirmed the removal of the hemicellulose and lignin from PC after alkali and bleaching treatments. The TGA analysis showed that the thermal stability of the CNCs is affected mainly by the dehydration reaction caused by sulfate groups. The SEM and FE-SEM images showed that after chemical treatments, defibrillation of fibers occurs and CNCs have a needle/rod like structure. Also, the specific surface aera was greatly increased from 0.495 for PC to 486.430 m²/g for CNCs. Herein, for the first time, lignin-containing cellulose extracted from PC was replaced with sawdust (SRB) in the production of alumina refractory bricks (RBs), as a pore former/binder. Interestingly, the prepared RBs (PC–NaOH/RB) had a greater amount of alumina (83%) and a lower density (0.75 g/cm³) than SRB. The classification temperature increased from 1650 for SRB to 1717 °C for PC-NaOH/RB.     

Cellulose acetate ultrafiltration membranes reinforced by cellulose nanocrystals: Preparation and characterization

Cellulose nanocrystals (CNCs) were used as a sustainable additive to improve the hydrophilicity, permeability, antifouling, and mechanical properties of blend membranes. Different CNC loadings (0–1.2 wt %) in cellulose acetate (CA) membranes were studied. The blend membranes were prepared by a phase‐inversion process, and their chemical structure and morphological properties were characterized by attenuated total reflectance–Fourier transform infrared spectroscopy, scanning electron microscopy, porosity, and mean pore size and contact angle measurement. The blend membranes became more porous and more interconnected after the addition of CNCs. The thickness of the top layer decreased and a few large holes in the porous substrate appeared with increasing CNC loading. In comparison with the pure CA membranes, the pure water flux of the blend membranes increased with increasing CNC loading. It reaches a maximum value of 76 L m^?2 h^?1 when the CNC loading was 0.5 wt %. The antifouling properties of the CA membrane were significantly improved after the addition of CNCs, and the flux recovery ratio value increased to 68% with the addition of 0.5 wt % CNCs. In comparison with that of the pure CA membranes, the tensile strength of the composite membranes increased by 47%. This study demonstrated the importance of using sustainable CNCs to achieve great improvements in the physical and chemical performance of CA ultrafiltration membranes and provided an efficient method for preparing high‐performance membranes. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43946.     

Modified cellulose nanocrystals enhancement to mechanical properties and water resistance of vegetable oil-based waterborne polyurethane

Environmentally friendly and lightweight silylated cellulose nanocrystal (SCNCs)/waterborne polyurethane (WPU) composite films that exhibit excellent mechanical properties and water resistance were prepared. The cellulose nanocrystals (CNCs) of the filamentous structure were surface-modified by γ-aminopropyltriethoxysilane (APTES) and then introduced into a castor oil-based aqueous polyurethane (WPU) matrix by in situ polymerization. The morphology and silylation degree of CNCs were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier infrared transform spectroscopy at different APTES concentrations. The results showed that the surface of the nanocellulose crystal has the best silylation morphology and thermal stability with incorporation of 6 wt % APTES. The thermal stability, mechanical properties, surface morphology, and water resistance of the nanocomposites were investigated by TGA, tensile test, SEM and optical contact angle, water absorption test, and mechanical property test after immersed in water. It was found that the effective introduction of modified CNCs resulted in a significant increase in tensile strength at high levels, and the thermal stability and hydrophobicity of the material were improved simultaneously, reaching the percolation threshold at a 0.50 wt % SCNCs as determined theoretically. This study provided an approach to the design and development of surface-modified CNCs/vegetable oil-based polymer composites by using an appropriate concentration of silane coupling agent to modify CNCs and improve the compatibility between nanocellulose and vegetable oil-based polymer matrices. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48228.     

Development and characterization of bionanocomposites based on poly(3‐hydroxybutyrate) and cellulose nanocrystals for packaging applications

Poly(3‐hydroxybutyrate) (PHB)‐based bionanocomposites were prepared using various percentages of cellulose nanocrystals (CNCs) by a solution casting method. CNCs were prepared from microcrystalline cellulose using sulfuric acid hydrolysis. The influence of CNCs on PHB properties was evaluated using differential scanning calorimetry, Fourier transform infrared spectroscopy, X‐ray diffraction, thermogravimetry and tensile testing. Vapor permeation and light transmission of the materials were also measured. Differential scanning calorimetric tests demonstrated that CNCs were effective PHB nucleation agents. Tensile strength and Young's modulus of PHB increased with increasing CNC concentration. Moreover, the PHB/CNC bionanocomposites exhibited reduced water vapor permeation compared to neat PHB and had better UV barrier properties than commodity polymers such as polypropylene. It was found that nanocomposites with 6 wt% of CNCs had the optimum balance among thermal, mechanical and barrier properties. © 2016 Society of Chemical Industry