Vinylic graft copolymers of cellulose. II. Thermal degradation of cellulose and its vinylic copolymers and blends by differential scanning calorimetry

Flaqué, C.; Montserrat, S.

doi:10.1002/app.1991.070421213

Cited by 12 publications

(10 citation statements)

References 7 publications

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“…It can be found that the crystallinity index of fillers slightly decreases when the alkalization treatment is applied. A similar character of the dependence of cotton or ramie crystallinity during alkali treatment has been reported in recent works [51][52][53]. It is well known that the lignocellulosic fillers undergo three distinct process during mercerization [18,54,55]: fiber swelling, disruption of the crystalline areas and formation of new crystalline lattice after rinsing away the mercerization solution.…”

Section: Waxs Diffraction Analysissupporting

confidence: 74%

Influence of cellulose polymorphs on the polypropylene crystallization

Borysiak

2013

J Therm Anal Calorim

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Results of the hitherto research work on alkalisation of lignocellulosic materials have been much divergent. In view of the above, the subject of this study is mercerization of cellulose from pine wood. This choice of the subject permitted observation of transformation of cellulose I to cellulose II with no participation of other components of lignocellulosic materials. According to X-ray results, during mercerization the isolated cellulose was easily (completely) transformed into cellulose II variety, while the pine wood was converted more slowly to cellulose II polymorphs. Therefore, it could be concluded that the presence of lignin and hemicelluloses in wood prevented the transformation from cellulose I to II. The main objective of this research was to establish the effect of cellulose varieties on the nucleation ability of different fillers by using differential scanning calorimetry (DSC) and polarizing microscopy. The nucleating effect of the fillers occurs only in the presence of cellulose I variety. In contrast, the presence of cellulose II variety seems to practically eliminate the nucleating effect of the fillers. Moreover, nucleation of the mercerized wood (mixture of cellulose I and II) can be also observed, but this effect is not strong. It should be emphasised that as yet no correlation has been reported between the quantitative composition of cellulose polymorphic forms (appearing not only in wood, but in cellulose isolated from wood as well) and the nucleation ability of lignocellulosic fillers.

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Section: Waxs Diffraction Analysissupporting

confidence: 74%

Influence of cellulose polymorphs on the polypropylene crystallization

Borysiak

2013

J Therm Anal Calorim

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“…Additional study with the purpose of determining the stability of the ester bonds between the straw and the modifier. Flaque and Montserrat 52 have shown that the presence of free hydroxyl groups influences the thermal stability of cellulose. They have proved that for copolymers grafted with cellulose, their intramolecular dehydration is impossible as –OH groups were substituted.…”

Section: Resultsmentioning

confidence: 99%

Modification of rapeseed straw with organic acid anhydrides

Paukszta

Doczekalska

Ostrowski

et al. 2014

Journal of Composite Materials

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Modification of lignocellulose materials, used as fillers in the composites with polyolefins, is applied to improve their adhesion to the matrix. One of the most often applied methods of such modification is the treatment with organic acid anhydrides. Rapeseed straw was modified with anhydrides of acetic, maleic and succinic acids. Such a modification changes the straw surface leading to the exposition of the wood tissue skeleton. The character changes depending on the type of anhydride applied. Esterification of repeseed straw by organic acid anhydrides resulted in changes in its chemical structure. According to infrared analysis of modified straw, new carbonyl groups were formed, as indicated by the absorption band in the range 1750–1730 cm−1. The degree of straw modification, measured by the weight percent gain index, informs about similar reactivities of the lignocelluloses material with all three anhydrides of organic acids used as modifiers. The starting temperatures of active thermolysis for the straw modified with maleic and succinic acid anhydrides were lower than that for native straw, while that for the straw modified with acetic acid was higher. Concentration of free radicals in rapeseed straw samples was measured by electron paramagnetic resonance spectroscopy. It was found that the maximum concentration of radicals for rapeseed straw was treated with maleic anhydride.

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“…50,51 Previous investigation on mercerization of cotton or ramie has shown that the crystallinity of cellulose decreases as a result of this treatment. Alkali treatment decreases the crystallinity index of wood to 42% (for 17.5% NaOH) and 58% (for 10% NaOH).…”

Section: Effect Of Treatment On the Supermolecular Structure Of Woodmentioning

confidence: 99%

“…A similar character of the dependence of cellulose crystallinity on NaOH concentration during alkali treatment has been in recent works. 50,51 Previous investigation on mercerization of cotton or ramie has shown that the crystallinity of cellulose decreases as a result of this treatment.…”

Section: Effect Of Treatment On the Supermolecular Structure Of Woodmentioning

confidence: 99%

Fundamental studies on lignocellulose/polypropylene composites: Effects of wood treatment on the transcrystalline morphology and mechanical properties

Borysiak

2012

J of Applied Polymer Sci

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Effects of alkalization, esterification, and c-irradiation of wood on the transcrystalline morphology of wood/polypropylene composites were investigated using X-ray diffraction, hot stage optical microscopy, and scanning electron microscopy. The occurrence of transcrystallization in wood-polypropylene composites is strongly dependent on the type of chemical modification of lignocellulosic materials. A detailed analysis of the results obtained proved that the transcrystallization is strongly influenced by conditions of mercerization process of wood and kind of anhydrides. Moreover, it has been found that amount of cellulose in wood plays a key role in the development of transcrystallinity. The absence of cellulose in wood seems to be unfavorable for the growth of transcrystallinity. A relationship between mechanical properties of composites and the phenomena taking place at the polymer-filler interface, controlled by chemical modifications of lignocellulose components has been evaluated. It has been established that the mechanical properties of wood composites depend on the proper choice of a modifier and are obtained after optimization of the process of modification.

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Vinylic graft copolymers of cellulose. II. Thermal degradation of cellulose and its vinylic copolymers and blends by differential scanning calorimetry

Cited by 12 publications

References 7 publications

Influence of cellulose polymorphs on the polypropylene crystallization

Influence of cellulose polymorphs on the polypropylene crystallization

Modification of rapeseed straw with organic acid anhydrides

Fundamental studies on lignocellulose/polypropylene composites: Effects of wood treatment on the transcrystalline morphology and mechanical properties

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