The influence of matrix crystallinity on the mechanical performance of short-fibre composites – Based on homo-polypropylene and a random polypropylene copolymer reinforced with man-made cellulose and glass fibres

Franciszczak, P.; Wojnowski, Jacek; Kalniņš, Kaspars; Piesowicz, Elżbieta

doi:10.1016/j.compositesb.2019.02.046

Cited by 30 publications

(18 citation statements)

References 39 publications

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“…For the composite materials obtained from PP and hemp, we can observe, on the one hand, an increase in the enthalpy of melting ΔH m, and on the other hand a decrease in the crystallinity as the hemp fibre content from the composite decreased. Regarding the enthalpy of crystallisation, the higher the degree of crystallinity of the composite material, the higher the amount of heat released [ 53 , 54 ].…”

Section: Resultsmentioning

confidence: 99%

Characterisation of Hemp Fibres Reinforced Composites Using Thermoplastic Polymers as Matrices

Stelea

Filip²,

Lisă

et al. 2022

Polymers

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Hemp fibres used as a reinforcing agent and three polymeric matrices (polypropylene, bicomponent, recycled polyester) were used to obtain composite materials by needle punching and heat pressing. The influence of the hemp/matrix ratio and the nature of the matrix on the properties of the composites were analysed. The obtained composites were characterised by physical–mechanical indices, thermal analysis (thermogravimetry (TG), differential thermogravimetry (DTG) and Differential Scanning Calorimetry (DSC)), Fourier Transform Infrared Spectroscopy (FTIR-ATR) analysis, Scanning Electron Microscopy (SEM) and Chromatic measurements. The mechanical properties of composites are influenced by both the hemp/matrix ratio and the nature of the matrix. The thermal stability of composites decreased as the amount of hemp increased (for the same mass losses, the decomposition temperature decreased significantly for composites containing a quantity of hemp greater than 50%). Regarding the nature of the matrix, for the same mass loss, the highest decomposition temperature was presented by the composites containing recycled polyester as matrix, and the lowest one was presented by composites containing polypropylene fibres as matrix. The FTIR and SEM analyses highlight the changes that occurred in the structure of the composite, changes determined both by the amount of hemp in the composite and by the nature of the matrix.

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Section: Resultsmentioning

confidence: 99%

Characterisation of Hemp Fibres Reinforced Composites Using Thermoplastic Polymers as Matrices

Stelea

Filip²,

Lisă

et al. 2022

Polymers

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“…Their ductility is also not reduced as they all break at around ~30% of strain. This gain can be attributed to reduced creep by the presence of HNT nanoclay or increased crystallinity owing to the nucleating effect of HNTs [ 28 , 29 , 30 ]. However, further addition of HNTs diminished the gain and for 10 vol.% content of HNTs, the tensile strength is even reduced by 7%, while the strain to break is reduced to 2.8%.…”

Section: Resultsmentioning

confidence: 99%

“…It is reduced by 5%, 14%, 18%, and 56% for nanocomposites with 1, 2, 5, and 10 vol.% of HNTs, respectively. Although, in some cases, the nanofillers improve the impact strength by increased crystallinity or a favorable change in crystal morphology [ 28 ], as well as other mechanisms reducing microcracking [ 31 , 32 ], their high modulus combined with low aspect ratio may also lead to reduction in impact strength, as in the case of reinforcing with fillers of higher magnitude [ 26 , 27 ]. In turn, reinforcing the PP matrix with short kenaf fibers gives ample rise of notched impact strength by 29%.…”

Section: Resultsmentioning

confidence: 99%

Effect of Halloysite Nanotube on Mechanical Properties, Thermal Stability and Morphology of Polypropylene and Polypropylene/Short Kenaf Fibers Hybrid Biocomposites

Franciszczak¹,

Taraghi²,

Paszkiewicz³

et al. 2020

Materials

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In this article, the effect of the addition of halloysite nanotube (HNT) on the mechanical and thermal stability of polypropylene (PP) and PP/kenaf fiber biocomposites has been investigated. Different volume contents of HNTs ranging from 1 to 10 vol.% were melt mixed with PP and PP/kenaf fibers. The volume content of kenaf fibers was kept constant at 30%. The morphology of HNTs within the PP matrix has been studied via scanning electron microscopy (SEM). The morphological results revealed that HNT was uniformly dispersed in the PP matrix already at a low concentration of 1 and 2 vol.%. The mechanical properties of the manufactured nanocomposites and hybrid biocomposites such as Young’s modulus, tensile strength, elongation at break, flexural modulus, flexural strength, and notched Izod strength have been measured. The results show that Young’s modulus and strengths have been improved along with the addition of low content of HNTs. Moreover, the gain of notched Izod impact strength obtained by the addition of short kenaf fibers was maintained in hybrids with low concentrations of HNTs. Finally, the thermogravimetric analysis shows that at 10% and 50% weight loss, the thermal degradation rate of the PP and PP/kenaf biocomposites decreased by the addition of HNTs.

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“…[ 17 ] On the contrary, as a promising alternative material, polypropylene random copolymer (PPR), obtained from random copolymerization of propylene with a few ethylene monomers, is considered to be an ideal matrix to produce high‐toughness fiber composites. [ 18,19 ] This attributes that the homopolymer sequences are crystallizable to form a compound bi‐phase containing crystalline and amorphous phases, while the propylene‐ethylene random segments tend to form rubbery phases. [ 20 ] Thus, this multiphase polyolefin system endows PPR with excellent rigidity‐toughness balance.…”

Section: Introductionmentioning

confidence: 99%

“…However, these studies only discussed the influence of nanomaterials on the crystallization temperature when discussing the influence of nanomaterials on the crystallization behavior of the PPR matrix; moreover, they did not only reveal the changes in the size distribution of crystallites from the perspective of crystallization and nucleation mechanisms, but also did not establish the relationship between crystallization parameters and mechanical properties. Besides, even though in glass fiber‐reinforced PPR systems, such as PPR/GF(80/20,60/40), [ 31 ] PPR/GF(75/25), [ 18 ] PPR/GF(40/60), [ 12 ] they only proved that PPR composites had better toughness than iPP composites, but did not further improve the toughness by adding β ‐NA. Therefore, the role of glass fiber alone or together with the β ‐NA in the crystallization process of the PPR matrix is still unknown.…”

Section: Introductionmentioning

confidence: 99%

Improved impact property of long glass fiber‐reinforced polypropylene random copolymer composites toughened with beta‐nucleating agent via tunning the crystallization and phase

et al. 2021

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Crystallization and phase engineering offer a promising route to significantly improve the impact property of long glass fiber‐reinforced polypropylene random copolymer (LGF/PPR) composites. However, the nucleation and crystallization mechanism in the crystallization process, and the resulting phase change mechanism are still unclear, which severely limits the remarkable improvement of the toughness of LGF/PPR composites. Herein, we successfully fabricate toughened LGF/PPR composites with excellent heat deflection temperature and impact toughness via tuning the crystallization behavior and phase structure generated by introducing β‐nucleating agent (β‐NA). Through differential scanning calorimeter and wide‐angle X‐ray diffraction analysis, the influence of LGF and β‐NA on the nucleation and crystallization mechanism of the PPR matrix was revealed. Therefore, the critical crystallization parameters were calculated, and then the correlation was established with tensile and impact properties through regression analysis. The results show that the impact strength of β‐PPR and β‐LGF/PPR/MPPR are remarkably increased by 50.1% and 26.3% at the critical β‐NA content of 0.2 and 0.1 wt%, respectively, due to the intrinsic toughening mechanism. This work may pave the way for preparing a class of LGF/PPR composites with high‐impact toughness.

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The influence of matrix crystallinity on the mechanical performance of short-fibre composites – Based on homo-polypropylene and a random polypropylene copolymer reinforced with man-made cellulose and glass fibres

Cited by 30 publications

References 39 publications

Characterisation of Hemp Fibres Reinforced Composites Using Thermoplastic Polymers as Matrices

Characterisation of Hemp Fibres Reinforced Composites Using Thermoplastic Polymers as Matrices

Effect of Halloysite Nanotube on Mechanical Properties, Thermal Stability and Morphology of Polypropylene and Polypropylene/Short Kenaf Fibers Hybrid Biocomposites

Improved impact property of long glass fiber‐reinforced polypropylene random copolymer composites toughened with beta‐nucleating agent via tunning the crystallization and phase

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