An Efficient Method for Determination of the Degree of Substitution of Cellulose Esters of Long Chain Aliphatic Acids

Freire, Carmen S.R.; Silvestre, Armando J. D.; Neto, Carlos Pascoal; Rocha, R.M.A.

doi:10.1007/s10570-005-2203-2

Cited by 59 publications

(55 citation statements)

References 14 publications

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“…The details related to the preparation of the acid chlorides by the standard reaction of the corresponding fatty acids with thionyl chloride, the heterogeneous esterification reactions in both media (toluene and dimethylformamide) and the determination of the degree of cellulose substitution (DS) have already been described [6,17]. The conditions associated with all the modifications are summarized in Table 1.…”

Section: Fibers Modificationmentioning

confidence: 99%

Composites based on acylated cellulose fibers and low-density polyethylene: Effect of the fiber content, degree of substitution and fatty acid chain length on final properties

Freire

Silvestre

Neto

et al. 2008

Composites Science and Technology

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a b s t r a c tLow-density polyethylene was filled with unmodified and fatty acid (hexanoic, dodecanoic, octadecanoic and docosanoic acids) esterified cellulose fibers. The thermal and mechanical properties, morphology and the water absorption behavior of the ensuing composites were investigated. The chemical modification of the cellulose fibers with fatty acids clearly improved the interfacial adhesion with the matrix and hence the mechanical properties of the composites and decreased their water uptake capacity. The performance of the composites was strongly affected by the degree of substitution (DS) and the fatty chain length as indicated by the fact that esterified cellulose fibers with low DS gave composites with better mechanical properties.

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Section: Fibers Modificationmentioning

confidence: 99%

Composites based on acylated cellulose fibers and low-density polyethylene: Effect of the fiber content, degree of substitution and fatty acid chain length on final properties

Freire

Silvestre

Neto

et al. 2008

Composites Science and Technology

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“…Concerning E. globulus , the research has been mainly devoted to high-value components from bark residues (Freire et al 2002 ;Domingues et al 2010 ;Santos et al 2011 ) and to new applications of cellulose fibers (Freire et al 2005(Freire et al , 2006a(Freire et al ,b, 2008Cunha et al 2007aCunha et al ,b, 2010Fernandes et al 2011a ;Tom é et al 2011a ).…”

Section: Introductionmentioning

confidence: 99%

Novel cellulose-based composites based on nanofibrillated plant and bacterial cellulose: recent advances at the University of Aveiro – a review

Freire

Fernandes²,

Silvestre

et al. 2012

Holzforschung

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Abstract:The development of (nano)materials based on the renewable cellulose is a challenge. The present article provides a brief overview of the recent research efforts carried out at the CICECO Laboratory of the University of Aveiro on the development of novel composites based on nanofibrillated plant and bacterial cellulose embedded in natural and synthetic polymeric matrices such as poly(lactic acid), chitosan, starch, and pullulan. These materials have high potential for applications in packaging, paper coating, organic electronics, and biomedical products and devices.

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“…There are several cellulose derivatives as for example esters, but only three have commercial importance: cellulose acetate (CA); a mixed Cellulose ester of Acetate and Propionate (CAP) and a mixed of cellulose acetate and butyrate (CAB) [5]. CAP is a commercial ester obtained from modification of cellulose and it can be used to synthesis of network chains, as described in this work.…”

Section: Introductionmentioning

confidence: 99%

“…The modification of cellulose normally forms a less crystalline material due to reduced intra and intermolecular hydrogen bonding. The nature of the substituent group and the extent, to which the hydroxyl groups are replaced, can provoke different thermal, mechanical and physical properties in the cellulose derivatives [5].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of a New Cellulose Acetate-Propionate Gel: Crosslinking Density Determination

Dantas¹,

Botaro²

2012

OJPChem

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Crosslinking is one of the most commonly reactions used to improve the physical properties of cellulose derivatives. Cellulose Acetate Propionate (CAP) is a commercial ester obtained as a cellulose derivative and it can be used as basis for the synthesis of crosslinked chains as described in this work. Typical used crosslinkers are di-functional compounds, such as dianhydrides or diisocyanate. The formation of polymeric 3D structures as described in this work occurs typically by the reaction of the linear chains bearing free OH groups with crosslinking agents such as dianhydrides. These reactions are used to make a very absorbent material, typically a gel. The syntheses were performed in homogeneous medium with acetate propionate in a very dry atmosphere by employing PMDA (Pyromellitic Dianhydride) and BTDA (3,3', 4,4' Benzophenone Tetracarboxylated Dianhydride) as crosslinking agents in a reflux system. TGA analysis has shown the different thermal stability of the gels when compared with CAP. Typical TGA curves have demonstrated the lower stability of the crosslinked chains when compared to CAP as consequence of esther linkages formed in the gels structures. The Mc, which is the value for the molar mass between crosslinkings points in 3D structure, was determined according to Flory-Rehner theory. This important parameter has demonstrated greater reactivity of PMDA in comparison with the BTDA in the reactions conditions' employed in this work.

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An Efficient Method for Determination of the Degree of Substitution of Cellulose Esters of Long Chain Aliphatic Acids

Cited by 59 publications

References 14 publications

Composites based on acylated cellulose fibers and low-density polyethylene: Effect of the fiber content, degree of substitution and fatty acid chain length on final properties

Composites based on acylated cellulose fibers and low-density polyethylene: Effect of the fiber content, degree of substitution and fatty acid chain length on final properties

Novel cellulose-based composites based on nanofibrillated plant and bacterial cellulose: recent advances at the University of Aveiro – a review

Synthesis and Characterization of a New Cellulose Acetate-Propionate Gel: Crosslinking Density Determination

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