scholarly journals Accelerated aging of WPCs Based on Polypropylene and Birch plywood Sanding Dust

2021 ◽  
Vol 11 (1) ◽  
pp. 319-328
Author(s):  
Janis Kajaks ◽  
Karlis Kalnins ◽  
Juris Matvejs
Keyword(s):  
Accelerated Aging ◽  
Degree Of Crystallinity ◽  
Accelerated Weathering ◽  
Recrystallization Process ◽  
Surface Layers ◽  
Uv Aging ◽  
Polypropylene Composites ◽  
Weathering Processes ◽  
Melting Temperatures ◽  
Dsc Measurements

Abstract A lot of researchers are closely related with natural, lignocellulose fibre containing bio-composites production and studies. Various of polymer matrices, mainly polyolefins, combinations with natural fibres as a reinforcement are used. Our studies are focused on polypropylene based bio-composites containing birch plywood production by-product sanding dust (PSD) accelerated weathering processes. The obtained results showed the following sight. After the aging the surface of all samples had faded, the changes of the gloss (decreasing) and of the whiteness degree (increasing) also had taken place, but microhardness of the surface of specimens significantly has decreased. The tensile strength and modulus of the samples after UV aging diminished about 30–35%. That indicates to the changes not only in the surface layers of polymer but also inside of the polymer structure. The FTIR measurements showed that during UV aging process occurs significant changes of chemical structure of the weathered surface of all samples. DSC measurements showed an increase of degree of crystallinity of the weathered polypropylene composites after the first heating due to the recrystallization process in the polypropylene matrix and a small decreasing after second heating. The melting temperatures of all composites after UV aging considerably diminish up to 30°C.

scholarly journals Accelerated Aging of WPCs Based on Polypropylene and Plywood Production Residues

2019 ◽  
Vol 9 (1) ◽  
pp. 115-128 ◽  
Author(s):  
Janis Kajaks ◽  
Karlis Kalnins ◽  
Juris Matvejs
Keyword(s):  
Total Duration ◽  
Tensile Modulus ◽  
Accelerated Aging ◽  
Degree Of Crystallinity ◽  
Accelerated Weathering ◽  
Recrystallization Process ◽  
Scanning Calorimetry ◽  
Sem Images ◽  
Weathering Processes ◽  
Polypropylene Matrix

AbstractA lot of researchers are closely connected with natural, lignocellulose fibre containing bio-composites producing and studies. Various of polymer matrices, mainly polyolefins, combinations with natural fibres as a reinforcement are used. Our studies are focused on polypropylene based bio-composites containing birch plywood production by-product sanding dust (PSD) accelerated weathering processes. The nine groups of the samples with different composition were exposed in an accelerated weathering chamber for a total duration of the 1032 h. The surface colour, gloss, whiteness degree, micro-hardness and the tensile properties of the samples during the weathering were tested. In addition, the weathered surfaces were characterized by scanning electron microscopy (SEM) studies and by differential scanning calorimetry (DSC) investigations. The obtained results showed the following sight: after the weathering the surface of all samples is faded, also the changes of the gloss and of the whiteness degree occurs, but microhardness of the surface of specimens has decreased. The tensile strength of the samples changes a little, in the same time the tensile modulus increases significantly due to the decrease of the deformation ability of the polypropylene matrix and recrystallization processes in PP. The SEM images taken at the 100 and 500 times of the magnification revealed a lot of the different shape and sizes cracks on the surface of the weathered samples. DSC measurements showed the increase of the degree of crystallinity of the polypropylene after the weathering due to the recrystallization process in the polypropylene matrix.

scholarly journals The Accelerated Aging Impact on Mechanical and Thermal Properties of Polypropylene Composites with Sedimentary Rock Opoka-Hybrid Natural Filler

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 338
Author(s):  
Paulina Jakubowska ◽  
Grzegorz Borkowski ◽  
Dariusz Brząkalski ◽  
Bogna Sztorch ◽  
Arkadiusz Kloziński ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Calcium Carbonate ◽  
Accelerated Aging ◽  
Natural Material ◽  
Accelerated Weathering ◽  
Mechanical And Thermal Properties ◽  
Hybrid Filler ◽  
Polypropylene Composites ◽  
Natural Filler ◽  
The Impact

This paper presents the impact of accelerated aging on selected mechanical and thermal properties of isotactic polypropylene (iPP) composites filled with sedimentary hybrid natural filler-Opoka rock. The filler was used in two forms: an industrial raw material originating as a subsieve fraction natural material, and a rock calcinated at 1000 °C for production of phosphorous sorbents. Fillers were incorporated with constant amount of 5 wt % of the resulting composite, and the material was subjected to accelerated weathering tests with different exposition times. The neat polypropylene and composites with calcium carbonate as a reference filler material were used for comparison. The aim of the research was to determine the possibility of using the Opoka rock as a new hybrid filler for polypropylene, which could be an alternative to the widely used calcium carbonate and silica. The thermal, mechanical, and structural properties were evaluated by means of differential scanning calorimetry (DSC), tensile tests, scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy with attenuated total reflectance (FTIR/ATR) prior to and after accelerated aging. As a result, it was found that the composites of polypropylene with Opoka were characterized by similar or higher functional properties and higher resistance to photodegradation compared to composites with conventional calcium carbonate. The results of measurements of mechanical properties, structural and surface changes, and the carbonyl index as a function of accelerated aging proved that Opoka was an effective ultraviolet (UV) stabilizer, significantly exceeding the reference calcium carbonate in this respect. The new hybrid filler of natural origin in the form of Opoka can therefore be used not only as a typical powder filler, but above all as a UV blocker/stabilizer, thus extending the life of polypropylene composites, especially for outdoor applications.

scholarly journals Post-Processing Time Dependence of Shrinkage and Mechanical Properties of Injection-Molded Polypropylene

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 22
Author(s):  
Artur Kościuszko ◽  
Dawid Marciniak ◽  
Dariusz Sykutera
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Injection Molding ◽  
Accelerated Aging ◽  
Mold Temperature ◽  
Degree Of Crystallinity ◽  
Injection Mold ◽  
Secondary Crystallization ◽  
Scanning Calorimetry ◽  
Injection Molded

Dimensions of the injection-molded semi-crystalline materials (polymeric products) decrease with the time that elapses from their formation. The post-molding shrinkage is an effect of secondary crystallization; the increase in the degree of polymer crystallinity leads to an increase in stiffness and decrease in impact strength of the polymer material. The aim of this study was to assess the changes in the values of post-molding shrinkage of polypropylene produced by injection molding at two different temperatures of the mold (20 °C and 80 °C), and conditioned for 504 h at 23 °C. Subsequently, the samples were annealed for 24 h at 140 °C in order to conduct their accelerated aging. The results of shrinkage tests were related to the changes of mechanical properties that accompany the secondary crystallization. The degree of crystallinity of the conditioned samples was determined by means of density measurements and differential scanning calorimetry. It was found that the changes in the length of the moldings that took place after removal from the injection mold were accompanied by an increase of 20% in the modulus of elasticity, regardless of the conditions under which the samples were made. The differences in the shrinkage and mechanical properties of the samples resulting from mold temperature, as determined by tensile test, were removed by annealing. However, the samples made at two different injection mold temperature values still significantly differed in impact strength, the values of which were clearly higher for the annealed samples compared to the results determined for the samples immediately after the injection molding.

Effect of Hybrid Fillers on the Thermal Properties of UHMWPE/Chitosan-ZnO Composites

2015 ◽  
Vol 754-755 ◽  
pp. 71-76
Author(s):  
Mohd Firdaus Omar ◽  
Lu Yew Wei ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Kamarudin Hussin
Keyword(s):  
Thermal Properties ◽  
Hybrid Composites ◽  
Degree Of Crystallinity ◽  
Reinforced Composites ◽  
Compression Technique ◽  
Melting Temperatures ◽  
Fusion Enthalpy ◽  
Reinforced Composite ◽  
Hybrid Fillers ◽  
Loss Level

In this work, UHMWPE reinforced composites containing hybrid zinc oxide (ZnO) and chitosan particles were prepared via the hot compression technique. The effect of ZnO contents (10, 20, 30 wt.%) and chitosan contents (1, 2, 3 wt.%) on the thermal properties of UHMWPE/ZnO and UHMWPE/Chitosan-ZnO reinforced composites were successfully investigated using DSC and TGA analysis, respectively. Based on DSC results, both UHMWPE/ZnO and hybrid composites did not record significant changes in the melting temperatures (Tm). The heat fusion enthalpy (Hm) and degree of crystallinity (Xc) of hybrid composites were found to be higher than UHMWPE/ZnO composites. As the TGA results shown, hybrid composites were also found to have higher thermal stability than UHMWPE/ZnO composites at 10 % and 50 % weight loss level. Overall, the UHMWPE/ZnO + 3 wt.% Chitosan hybrid reinforced composite recorded comparable mechanical properties and better thermal properties than neat UHMWPE.

scholarly journals Impact of environmental agents on non-woven polylactide/natural rubber agrofiber

2021 ◽  
Vol 285 ◽  
pp. 07034
Author(s):  
Yulia Tertyshnaya ◽  
Maksim Zakharov ◽  
Alina Ivanitskikh ◽  
Anatoliy Popov
Keyword(s):  
Natural Rubber ◽  
Uv Irradiation ◽  
Thermal Characteristics ◽  
Degree Of Crystallinity ◽  
Distilled Water ◽  
Fibrous Materials ◽  
Scanning Calorimetry ◽  
Melting Temperatures ◽  
Environmental Agents ◽  
The Degree Of Crystallinity

In the work an eco-friendly non-woven fiber made of polylactide and natural rubber with a rubber content from 0 to 15 wt.% was obtained by electrospinning. The influence of distilled water and UV irradiation on the agrofibers has been investigated. The water sorption test showed that the addition of natural rubber into the polylactide matrix does not significantly affect the degree of water absorption of the fibrous materials, which is in the range of 49-50.6%. Thermal characteristics after 180 days of degradation in distilled water at 22±2 oC and UV irradiation at a wavelength of 365 nm during 100 hours were determined using the differential scanning calorimetry. Changes in the values for glass transition and melting temperatures, and the degree of crystallinity were determined.

Feasibility Study of Chemical Treatments on Sorghum Fibres for Compatibility Enhancement in Polypropylene Composites

2018 ◽  
Vol 929 ◽  
pp. 70-77 ◽  
Author(s):  
Ismojo ◽  
Rai Pratama ◽  
Ghiska Ramahdita ◽  
Anne Zulfia Syahrial ◽  
Mochamad Chalid
Keyword(s):  
Crystallinity Index ◽  
Ester Group ◽  
Hydroxyl Group ◽  
Compatibility Study ◽  
Scanning Calorimetry ◽  
Polypropylene Composites ◽  
Dsc Measurements ◽  
Long Time ◽  
Weak Compatibility ◽  
Pp Composites

Polypropylene (PP) is one of the biggest petro-polymers, which is used in very wide application nowadays. The environment problem due to materials such as plastics having very long time degradability, and critical petroleum sources have promoted some studies to empowerment of natural resources such as natural fibres for substituting or at least modifying petro-polymers. Because of biodegradability obtained from natural source, sorghum fibers are interesting to be used as filler in PP composites, despite of weak compatibility between them. Surface modification on the sorghum fibers through alkalinization prior to acetylation was aimed to improve the fiber compatibility to PP. The treatments were expected to substitute hydroxyl group in the sorghum fibers, into acetic ester group in order to increase their hydrophobicity as the fillers. Moreover, the treatments were able to unbundle single fibers into micro-fibrillated cellulose (MFC) fibres with increase in crystallinity index. Usage of this MFC fiber as filler in PP leads to improvement of the composite performances such as thermal properties. In this study, Fourier Transformation Infra-Red (FTIR) Spectroscopy, X-ray Diffraction (XRD), Differential Scanning Calorimetry (DSC) and Field-Emission Scanning Electron Microscope (FE-SEM) were used to evaluate the performances of the Sorghum fibers after the treatments and as the filler in the Sorghum fibers/PP composites. The experimental results showed the MFC fibers as the smallest sizes in 5.0 microns and the highest crystallinity index up to 79.1 %, obtained from alkalinization with 2.5 M NaOH prior to acetylation with 17.4 M CH3COOH and the glacial (CH3CO2)2. Compatibility study of the treated Sorghum fibers on PP shows an improvement indicated by a strong interaction between the fibers and PP on morphology observation, increase in melting point of PP from 163.4°C (using virgin Shorgum fibers) into 163.6°C (using treated Sorghum fibers) in DSC measurements.

Electrical conductivity of carbon nanotube/polypropylene composites prepared through microlayer extrusion technology

2017 ◽  
Vol 37 (8) ◽  
pp. 795-804 ◽  
Author(s):  
Changjin Li ◽  
Zhiwei Jiao ◽  
Liangzhao Xiong ◽  
Weimin Yang
Keyword(s):  
Electrical Conductivity ◽  
Polymer Matrix ◽  
Rotation Speed ◽  
Mapping Method ◽  
Degree Of Crystallinity ◽  
Polypropylene Composites ◽  
Multilayered Composites ◽  
Promising Application ◽  
Anisotropic Conducting ◽  
Extrusion Technology

Abstract The morphological distribution of carbon nanotubes (CNTs) in polymer matrix has a crucial impact on the performance of CNT-filled polymer composites. A novel microlayer extrusion technology used in the dispersion and orientation of CNTs was proposed, and polypropylene (PP)/multiwalled CNT (MWCNT) composites with different numbers of layers were prepared with it. The MWCNT dispersion was investigated by scanning electron microscopy and Raman mapping method, and the MWCNT orientation was quantified by Raman spectroscopy. The influences of the dispersion and orientation of MWCNTs on the electrical conductivity and crystallization behavior of the composites were investigated. The results showed that the anisotropic conducting properties of the multilayered composites varied distinguishably with the increase of layer numbers and rotation speed. Furthermore, the degree of crystallinity of PP increased when the layer number increased from 1 to 729. All of these results suggest that with the increase of the layer numbers and the rotation speed, the dispersion and orientation of MWCNTs in PP matrix improve greatly. Overall, we provide an efficient and practical approach to control the dispersion and orientation of CNT in polymer matrix, which has a promising application prospect in the field of plastic processing.

Interfacial properties of all-polypropylene composites

e-Polymers ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Shadi Houshyar ◽  
Robert A. Shanks
Keyword(s):  
Optical Microscope ◽  
Processing Conditions ◽  
Polypropylene Composites ◽  
Melting Temperatures ◽  
Pull Out ◽  
Physico Chemical ◽  
Microbond Test ◽  
The Matrix ◽  
The Difference ◽  
Poly Propylene

AbstractPreparation and characterization of novel composites, consisting of polypropylene (PP) fibres in a random poly(propylene-co-ethylene) (PPE) matrix, were investigated. These composites possess unique properties, due to chemical compatibility of the two polymers allowing creation of strong physico-chemical interactions and strong interfacial bonds. The difference between the melting temperatures of PP fibre and PPE was exploited in order to establish processing conditions for the composites. Suitable conditions were chosen so that the matrix was a liquid, to ensure good wetting and impregnation of the fibres, though the temperature must not be high enough to melt the fibres. The morphology of the composites was investigated using optical and scanning electron microscopy. Optical microscope images showed that transcrystallization of the matrix was observed on PP fibre surfaces. SEM photographs displayed a thin layer of matrix on the reinforcement, attributed to good impregnation and wetting of the fibres. Adhesion between PPE matrix and PP fibres was characterized using a microbond test inspired by a fibre pull-out technique. The results showed that adhesion was appreciably increased when PP fibres were used instead of glass fibres in the matrix. Nevertheless, thermal processing conditions of the composites caused reduction in mechanical behaviour of the reinforcement.

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