X-Ray Diffractometer Thermal Technique for Study of Structural Changes in Cellulosic Compounds1

Creely, Joseph J.

doi:10.1177/004051756203200303

Cited by 11 publications

(2 citation statements)

References 7 publications

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“…25 and Creely and Conrad. 26 These results indicate the exothermic peak at 478 K in DSC curve of the Polymer J., Vol. 17, No.8, 1985 fraction T A3-4 is caused by crystallization.…”

Section: Ca(292)mentioning

confidence: 72%

Thermal Analysis of Cellulose Acetate Solids with Total Degrees of Substitution of 0.49, 1.75, 2.46, and 2.92

Kamide

Saito

1985

Polym J

113

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ABSTRACT:The effects of the total degree of substitution {F)) and average-molecular weight on glass transition temperature (Tg), melting point (Tm) and the onset point of thermal decomposition (Tctl for cellulose acetate (CA) solids were studied using DSC, TG, and X-ray diffractometry. Fractionated and whole CA polymers with {F)) of 0.49, 1.75, 2.46, and 2.92 were used. All whole and fractionated CA showed Tg. Tg of CA fractions do not depend on averagemolecular weight significantly, except for CA(2.92) (the number in parentheses denotes {F))). Tg of CA fractions increases monotonously with a decrease in {F)) as follows Tg(K) = 523-20.3{F))

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“…25 and Creely and Conrad. 26 These results indicate the exothermic peak at 478 K in DSC curve of the Polymer J., Vol. 17, No.8, 1985 fraction T A3-4 is caused by crystallization.…”

Section: Ca(292)mentioning

confidence: 72%

Thermal Analysis of Cellulose Acetate Solids with Total Degrees of Substitution of 0.49, 1.75, 2.46, and 2.92

Kamide

Saito

1985

Polym J

113

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“…As the last part of the chemical analysis, the FTIR spectra of Seifert cellulose were analyzed using the Nicolet iS20 spectrophotometer (Waltham, MA, USA). The increase in the crystallinity of wood cellulose by heat treatment has been reported by many studies [ 48 , 49 , 50 ]. The crystalline state significantly influences other properties such as the elasticity, absorptive capacity, and other industrially valuable physical properties of the fiber.…”

Section: Methodsmentioning

confidence: 82%

Degradation of Chemical Components of Thermally Modified Robinia pseudoacacia L. Wood and Its Effect on the Change in Mechanical Properties

Síkora

Hájková

Jurczyková

2022

IJMS

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Currently, emphasis is placed on using environmentally friendly materials both from a structural point of view and the application of protective means. For this reason, it is advisable to deal with the thermal modification of wood, which does not require the application of protective substances, to increase its service life. The main reason for the thermal modification of black locust is that although black locust grows abundantly in our country, it has no industrial use. It is mainly used outdoors, where thermal modification could increase its resistance. This article deals with the thermal modification of black locust wood (Robinia pseudoacacia L.) and the impact of this modification on the chemical components of the wood with an overlap in the change in mechanical properties compared to untreated wood. Static (LOP, MOR, and MOE) and dynamic (IBS) bending properties were evaluated as representative mechanical properties. At the same time, the impact of thermal modification on the representation of chemical components of wood (cellulose, lignin, hemicellulose) was also tested. As a result of the heat treatment, the mechanical properties gradually decreased as the temperature increased. The highest decrease in mechanical values found at 210 °C was 43.7% for LOP and 45.1% for MOR. Thermal modification caused a decrease in the content of wood polysaccharides (the decrease in hemicelluloses content was 33.2% and the drop in cellulose was about 29.9% in samples treated at 210 °C), but the relative amount of lignin in the wood subjected to increased temperature was higher due to autocondensation, and mainly because of polysaccharide loss. Based on the correlations between chemical and mechanical changes caused by thermal modification, it is possible to observe the effects of reducing the proportions of chemical components and changes in their characteristic properties (DP, TCI) on the reduction in mechanical properties. The results of this research serve to better understand the behavior of black locust wood during thermal modification, which can primarily be used to increase its application use.

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Thermoplasticity of acetylated cotton yarn as influenced by degree of substitution, temperature, and other factors

Creely

Harbrink

1965

J of Applied Polymer Sci

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synopsisThe relative degree of thermoplasticity of acetylated cotton yarns has been deteimined by a technique developed for the purpose. The interfering contribution of hydrogen bonding could be eliminated by a wetting-out process. The yarns were acetylated to degrees of substitutions ranging from 0.77 to 2.93. Heat setting was applied either in vacuum or at atmospheric pressure in the presence of water vapor a t temperatures in the range of 110-225OC. The thermoplasticity observed over a period of 30 days was permanent but readily removable by another application of heat setting. The effect of degree of substitution upon thermoplasticity could be represented by sigmoidal curves beginning at about DS = 1 and increasing rapidly and asymptotically to a maximum a t about DS = 2.25. In vacuum or water vapor the maximum thermoplastic response occurred a t 175"C., but the response was greater with water vapor. Under vacuum heating a very distinct minimum response occurs a t 18OoC., due to second-order transition effect. Upon heating in the presence of water vapor a distinct minimum response occurs at 200°C. with secondary minima at 150 and 120'C. Prior crystallization (by heating to 200-225°C.) greatly reduces thermoplasticity due to reduction of the amorphous component, but does not completely eliminate it.

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X-Ray Diffractometer Thermal Technique for Study of Structural Changes in Cellulosic Compounds1

Cited by 11 publications

References 7 publications

Thermal Analysis of Cellulose Acetate Solids with Total Degrees of Substitution of 0.49, 1.75, 2.46, and 2.92

Thermal Analysis of Cellulose Acetate Solids with Total Degrees of Substitution of 0.49, 1.75, 2.46, and 2.92

Degradation of Chemical Components of Thermally Modified Robinia pseudoacacia L. Wood and Its Effect on the Change in Mechanical Properties

Thermoplasticity of acetylated cotton yarn as influenced by degree of substitution, temperature, and other factors

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