Structure and thermal properties of poly(lactic acid)/cellulose whiskers nanocomposite materials

Petersson, Linnéa; Kvien, Ingvild; Oksman, Kristiina

doi:10.1016/j.compscitech.2006.12.012

Cited by 547 publications

(339 citation statements)

References 21 publications

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“…Freeze-drying represents a potential option, because it largely preserves the fibrillary structure of MFC without agglomeration during the drying process (Peng et al 2012). Nanocellulose powder was prepared by combining freezing drying and surfactant treatment, and it was re-dispersed in PLA-chloroform solution to prepare PLA composites (Petersson et al 2007). Drying in supercritical CO2 is also a good way to produce dry NFC, as it keeps the dimensions in nano size (Peng et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Dry, hydrophobic microfibrillated cellulose powder obtained in a simple procedure using alkyl ketene dimer

et al. 2016

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In order to produce dry and hydrophobic microfibrillated cellulose (MFC) in a simple procedure, its modification with alkyl ketene dimer (AKD) was performed. For this purpose, MFC was solventexchanged to ethyl acetate and mixed with AKD dissolved in the same solvent. Curing at 130°C for 20 h under the catalysis of 1-methylimidazole yielded a dry powder. Scanning electron microscopy of the powder indicated loss in nanofibrillar structure due to aggregation, but discrete microfibrillar structures were still present. Water contact angle measurements of films produced from modified and unmodified MFC showed high hydrophobicity after AKD treatment, which persisted even after extraction with THF for 8 h. The hydrophobized MFC was characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance and X-ray analysis. In summary, strong indications for the presence of AKD on the surface of MFC before and after extraction with solvent were found, but only a very small amount of covalent b-ketoester linkages between the modification agent and cellulose was revealed.

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Section: Introductionmentioning

confidence: 99%

Dry, hydrophobic microfibrillated cellulose powder obtained in a simple procedure using alkyl ketene dimer

et al. 2016

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“…Furthermore, as observed by Bondeson and Oksman [21] the surfactants may cause degradation of the polymer matrix. On the other hand, Peterson et al [19] reports that when lyophilizing a suspension of whiskers in aqueous medium and after their dispersion in chloroform, undesirable flakes are formed in the solvent. Viet et al [46] studied a suspension of lyophilized whiskers in aqueous medium and their subsequent dispersion in dimethylformamide and dimethyl sulfoxide, while maintaining the aggregates in the suspension.…”

Section: Characterization Of Whiskersmentioning

confidence: 99%

“…However, this restricts their use in the matrices of hydrophobic polymers due to difficulties related to their dispersion in these systems. Studies have been directed toward obtaining an adequate dispersion of whiskers in hydrophobic matrices, using approaches such as the addition of anionic surfactants or tert-butanol to the dispersing medium [19] , the use of a cationic surfactant [20] , the use of partially hydrolyzed poly(vinyl alcohol) [21] , surface functionalization of the whiskers [22][23][24] , the use of lyophilization and redispersion in a non-aqueous solvent. Of these proposed methods, the redispersion of the whiskers in non-aqueous solvents has proved to be a promising technique which allows homogeneous dispersion in hydrophobic polymers, it being necessary to assess the process conditions in relation to the polymer matrix.…”

Section: Introductionmentioning

confidence: 99%

Isolation of whiskers from natural sources and their dispersed in a non-aqueous medium

et al. 2016

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SbstractWhiskers have been used as a nanomaterial dispersed in polymer matrices to modify the microscopic and macroscopic properties of the polymer. These nanomaterials can be isolated from cellulose, one of the most abundant natural renewable sources of biodegradable polymer. In this study, whiskers were isolated from sugarcane bagasse and corn cob straw fibers. Initially, the cellulose fiber was treated through an alkaline/oxidative process followed by acid hydrolysis. Dimethylformamide and dimethyl sulfoxide were used to replace the aqueous medium for the dispersion of the whiskers. For the solvent exchange, dimethylformamide or dimethyl sulfoxide was added to the aqueous dispersion and the water was then removed by fractional distillation. FTIR, TGA, XRD, TEM, Zeta and DLS techniques were used to evaluate the efficiency of the isolation process as well as the morphology and dimensions of the whiskers. The dimensions of the whiskers are comparable with values reported in the literature, maintaining the uniformity and homogeneity in both aqueous and non-aqueous solvents.

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“…The thermal stability, rigidity, and hardness of the resulting composite materials were improved due to the addition of NCC (Petersson et al 2007;Noorani et al 2007;Habibi et al 2010). The effects of the modified NCC (modified by APTES and MPS, respectively) on the HCHO emission and bonding strength of urea-formaldehyde (UF) resin adhesive were studied.…”

Section: Introductionmentioning

confidence: 99%

“…The addition of microcrystalline cellulose nanofibers into linear segmented polyurethanes (SPU) resulted in an increase in the Young's modulus and a decrease in the deformation at the break (Auad et al 2010). Recently, nanocrystalline cellulose (NCC) has been extensively studied because it exhibits many unique characteristics, such as high tensile strength and Young's modulus, polar groups (-OH), an enriched surface (Eyley and Thielemans 2011), and a high specific surface area (Cranston and Gray 2006;Zaman et al 2012) in addition to its biodegradable and environmentally benign nature (Wegner and Jones 2006).The thermal stability, rigidity, and hardness of the resulting composite materials were improved due to the addition of NCC (Petersson et al 2007;Noorani et al 2007;Habibi et al 2010). The effects of the modified NCC (modified by APTES and MPS, respectively) on the HCHO emission and bonding strength of urea-formaldehyde (UF) resin adhesive were studied.…”

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confidence: 99%

Preparation and Characterization of Waterborne Polyurethane Modified by Nanocrystalline Cellulose

et al. 2013

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Nanocrystalline cellulose (NCC) was used as a modifier for waterborne polyurethane (WPU) to investigate the water and ethanol resistance of WPU-NCC composites. The NCC surface was modified with γ-glycidoxypropyltrimethoxysilane (GPTMS) and γ-ammnonimpropylmethyldimethoxysilane (APMDS) to improve its compatibility with waterborne polyurethane (WPU), as indicated by the contact angle (CA). The characteristic properties of WPU modified by NCC and a control group were compared by a Fourier-transform infrared spectroscope (FTIR), X-ray powder diffraction (XRD), and scanning electron microscopy (SEM). The CA between the modified NCC and WPU was decreased by 31.2% (with 8.0% APMDS (v/v)), and the NCC modified by GPTMS resulted in a 33.8% decrease of the CA. Compared to the original WPU, the crystal structure and crystallinity of the modified WPU showed a slight alteration. The SEM micrographs showed that the NCC particles modified by GPTMS were dispersed more uniformly. The FT-IR results showed that the addition of modified NCC led to the reduction of the characteristic absorption peak of the hydroxyl group. The water resistance of WPU with 1.5% NCC modified by GPTMS was increased by 47.2%, and the ethanol resistance decreased by 67.0%, while the modification from APMDS led to a 38.1% increase in water resistance and a 56.9% decrease in ethanol resistance. Science and Technology, Beijing Forestry University, Haidian District, Beijing 100083, PR China;*Corresponding author: pujunwen@126.com Keywords INTRODUCTIONWaterborne polyurethane (WPU) has become used to a remarkable degree as a replacement for the ordinary solvent-based polyurethane, a change that has been motivated by its environment-friendly, nontoxic, and nonflammable nature (Wegner and Jones 2006;Du et al. 2008;Kim et al. 2010). WPU is considered to be an organic material with a wide potential of applications in many fields, such as coatings, adhesives, leathers, and the textile industry (Kim and Lee 1996;Madbouly and Otaigbe 2005;Cao et al. 2007). However, the waterborne polyurethanes are inferior to the solvent-based polyurethane with respect to their low chemical resistance, scratch resistance, weather resistance, mechanical strength, and gloss (Rahman and Lee 2009;Zhang et al. 2010). Due to the hydrophilic groups from the molecular chain of WPU, the dried film of WPU shows obvious hygroscopic properties, which lead to poor water resistance, low mechanical properties, and strength decreases. (Rahman and Kim 2007;Sun et al. 2011) Much attention has been given to overcoming these shortcomings and realizing the larger-scale application of WPU by the incorporation of organic and inorganic materials 2595 Zhang et al. 2010). The nanosilica was added into the aqueous emulsion of polyurethane (PU) in order to improve its water and thermal resistance. The improvement could be attributed to a thermal insulation effect of nanosilica, as well as an increase of the mean free path of water molecules that pass through the matrix of the PU-nanosilica composite (Kim e...

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Structure and thermal properties of poly(lactic acid)/cellulose whiskers nanocomposite materials

Cited by 547 publications

References 21 publications

Dry, hydrophobic microfibrillated cellulose powder obtained in a simple procedure using alkyl ketene dimer

Dry, hydrophobic microfibrillated cellulose powder obtained in a simple procedure using alkyl ketene dimer

Isolation of whiskers from natural sources and their dispersed in a non-aqueous medium

Preparation and Characterization of Waterborne Polyurethane Modified by Nanocrystalline Cellulose

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