Non-isothermal degradation kinetics of filled with rise husk ash polypropene composites

Turmanova, Sevdalina; Genieva, Svetlana; Dimitrova, Antonia; Vlaev, L. T.

doi:10.3144/expresspolymlett.2008.18

Cited by 278 publications

(141 citation statements)

References 49 publications

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“…Generally, the kinetic equation and the reaction rate of the chemical reactions can be written as follows [9,23,27,28]:…”

Section: Theoretical Approach and Mathematical Backgroundmentioning

confidence: 99%

“…If the studies are carried out under a linear increase of the temperature dT/dt = q = const, Equation (1) may be rewritten as follows [23,27,28]:…”

Section: Theoretical Approach and Mathematical Backgroundmentioning

confidence: 99%

“…On the other hand, when high activation entropy values are observed, the material is far from its own thermodynamic equilibrium. In this case, the reactivity is high, and the system can react faster to produce the activated complex, which gives shorter observed reaction times [22,23]. Studies of the kinetics of a number of similar chemical reactions, both homogeneous and heterogeneous, show that there is a growing linear dependence between the activation energy E A and the change of the entropy ΔS / = at the formation of the activated complex from the reagents [24][25][26].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Kinetics of Nonisothermal Degradation of Some Polymer Composites: Change of Entropy at the Formation of the Activated Complex from the Reagents

Turmanova

Genieva

Vlaev

2011

Journal of Thermodynamics

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Studying the nonisothermal kinetics of degradation of rice husks in air or nitrogen atmosphere, polypropylene and tetrafluoroethylene-ethylene copolymer filled with different quantities of rice husks flour or the products of its thermal degradation, namely "white" or "black" rice husks ash, a linear dependence was observed between the ln A and E A , known as the kinetic compensation effect or theta rule. A linear relationship was also established between E A and the change of the entropy ΔS / = for the formation of the activated complex from the reagents. These dependences are related to the assumption of identical kinetic mechanisms of thermal degradation of the composites studied. The negative values of ΔS / = obtained show that the activated complex is a "more organized" structure than the initial reactants and that these reactions may be classified as "slow" ones. It may be concluded that the products of the thermal degradation of rice husks in a fluidized bed reactor can successfully replace the more expensive synthetic fillers to obtain different polymer composites. These polymer composites can lead to the futuristic "organic-inorganic hybrid materials" with specific properties.

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“…Generally, the kinetic equation and the reaction rate of the chemical reactions can be written as follows [9,23,27,28]:…”

Section: Theoretical Approach and Mathematical Backgroundmentioning

confidence: 99%

“…If the studies are carried out under a linear increase of the temperature dT/dt = q = const, Equation (1) may be rewritten as follows [23,27,28]:…”

Section: Theoretical Approach and Mathematical Backgroundmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Kinetics of Nonisothermal Degradation of Some Polymer Composites: Change of Entropy at the Formation of the Activated Complex from the Reagents

Turmanova

Genieva

Vlaev

2011

Journal of Thermodynamics

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“…The composition of natural fibres includes cellulose, hemicellulose, lignin, pectin, fat, waxes and water soluble substances [1][2][3]. The composition may differ with the growing condition and test methods even for the same kind of fiber [4].…”

Section: Introductionmentioning

confidence: 99%

The effects of acetylation on properties of flax fibre and its polypropylene composites

Błędzki¹,

Mamun²,

Lucka-Gabor³

et al. 2008

Express Polym. Lett.

415

233

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Abstract. Flax fibre was modified with acetylation. The influence of the acetylation on the structure and properties of flax fibre were investigated as well as modified flax fibre reinforced polypropylene composites were also prepared. The catalyst was used to accelerate acetylation reaction rate. Flax fibre was characterised after modification. Surface morphology, moisture absorption property, components content, degree of polymerisation, crystallinity of cellulose and thermal stability of flax fibres were studied. Due to acetylation, the flax fibre surface morphology and moisture resistance properties improved remarkably. Flax fibre (modified and unmodified) reinforced polypropylene composites were fabricated with 30 wt% fibre loading. The mechanical properties were investigated for those composites. Tensile and flexural strengths of composites were found to increase with increasing degree of acetylation up to 18% and then decreased. Charpy impact strengths of composites were found to decrease with increasing degree of acetylation. Owing to addition of coupling agent (maleated polypropylene -MAH), the tensile and flexural strength properties were found to increase in between 20 to 35% depending on degree of acetylation.

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“…All-PP composites require a difference between the matrix-PP and the PP fibres that will allow the matrix to consolidate by fusion without changing the fibres, this difference maybe a PP copolymer or even differing orientation [9]. All-PP composites combine by a process analogous to welding [10] and eliminate typical interfacial weakness problems or need for compatabilisers when non-polar PP is used with inorganic fillers [11,12]. PP grafted with maleic anhydride is often used as a compatabiliser [13] though additional modification of fillers may be used [14].…”

Section: Introductionmentioning

confidence: 99%

Modelling of polypropylene fibre-matrix composites using finite element analysis

Houshyar¹,

Shanks²,

Hodzic³

2009

Express Polym. Lett.

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Abstract. Polypropylene (PP) fibre-matrix composites previously prepared and studied experimentally were modelled using finite element analysis (FEA) in this work. FEA confirmed that fibre content and composition controlled stress distribution in all-PP composites. The stress concentration at the fibre-matrix interface became greater with less fibre content. Variations in fibre composition were more significant in higher stress regions of the composites. When fibre modulus increased, the stress concentration at the fibres decreased and the shear stress at the fibre-matrix interface became more intense. The ratio between matrix modulus and fibre modulus was important, as was the interfacial stress in reducing premature interfacial failure and increasing mechanical properties. The model demonstrated that with low fibre concentration, there were insufficient fibres to distribute the applied stress. Under these conditions the matrix yielded when the applied stress reached the matrix yield stress, resulting in increased fibre axial stress. When the fibre content was high, there was matrix depletion and stress transfer was inefficient. The predictions of the FEA model were consistent with experimental and published data.

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Non-isothermal degradation kinetics of filled with rise husk ash polypropene composites

Cited by 278 publications

References 49 publications

Kinetics of Nonisothermal Degradation of Some Polymer Composites: Change of Entropy at the Formation of the Activated Complex from the Reagents

Kinetics of Nonisothermal Degradation of Some Polymer Composites: Change of Entropy at the Formation of the Activated Complex from the Reagents

The effects of acetylation on properties of flax fibre and its polypropylene composites

Modelling of polypropylene fibre-matrix composites using finite element analysis

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