scholarly journals Improving Mechanical Properties of PLA/Starch Blends Using Masterbatch Containing Vegetable Oil Based Active Ingredients

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2981
Author(s):  
Bianka Nagy ◽  
Norbert Miskolczi ◽  
Zoltán Eller

The aim of this research was to increase the compatibility between PLA and starch with vegetable oil-based additives. Based on tensile results, it can be stated, that Charpy impact strength could be improved for 70/30 and 60/40 blends in both unconditioned and conditioned cases, regardless of vegetable oil, while no advantageous change in impact strength was obtained with PLA-g-MA. Considering sample with the highest starch concentration (50%), the flexural modulus was improved by using sunflower oil-based additive, Charpy impact strength and elongation at break was increased using rapeseed oil-based additive in both conditioned and unconditioned cases. SEM images confirmed the improvement of compatibility between components.

2013 ◽  
Vol 747 ◽  
pp. 395-398 ◽  
Author(s):  
Ahmad Bilal ◽  
Richard Lin ◽  
Krishnan Jayaraman

In recent years, the use of agro-wastes, such as rice husk (RH), in the manufacture of thermoplastic composites to replace wood fibres has emerged as a promising field of interest. Linear medium density polyethylene (LMDPE) and ground rice husk (GRH) were used to manufacture composites. The D-optimal design routine in Design Expert software was used to select ten different blends with different percentages of RH, MDPE and compatibiliser, maleated polyethylene (MAPE) along with four replicate blends. RH was varied between 15 to 50 wt%, MAPE between 1 to 6 wt% and MDPE between 44 to 84 wt%. The effects of RH, MDPE and MAPE content on the mechanical properties of the manufactured composites were examined. The results show that tensile and flexural properties of the composites were improved, whereas, Charpy impact strength was decreased with increasing RH loading. The effect of MAPE on tensile strength and Charpy impact strength was significant, but its effect was negligible on tensile modulus, flexural strength and flexural modulus of the composites.


Recycling ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 76
Author(s):  
Abdelhak Ladhari ◽  
Esra Kucukpinar ◽  
Henning Stoll ◽  
Sven Sängerlaub

Polypropylene (PP) has a high recycling potential. However, the properties of mechanically recycled PP (R-PP) have not been fully compared to those of virgin PP (V-PP). Therefore, in this study, properties of R-PP and V-PP were compared using data from recyclers, virgin plastic suppliers, and the literature. The properties of recyclates could not be directly correlated either with the properties of the virgin polymers from which the recyclates were made or the recycling parameters. It was found that the MFR of R-PP was higher; MFR R-PP had a median value (m) of 11 g/10 min while MFR V-PP had a median value of 6.3 g/10 min (at 230 °C and with 2.16 kg). In terms of mechanical properties, in many cases R-PP exhibited stiffer and more brittle behavior, with a slightly higher Young’s modulus (ER-PP = 1400 and EV-PP = 1200 MPa), a reduced elongation at break (ɛbR-PP = 4 l.-% and ɛbV-PP = 83 l.-%), and notched charpy impact strength (NCISR-PP = 4.8 and NCISV-PP = 7.5 kJ/m2). However, the values for every property had a broad distribution. In addition to existing information from the literature, our research sheds fresh light on the variation of the characteristics of recycled polypropylenes presently on the market.


2011 ◽  
Vol 65 (6) ◽  
pp. 707-715 ◽  
Author(s):  
Pavle Spasojevic ◽  
Milorad Zrilic ◽  
Dragoslav Stamenkovic ◽  
Sava Velickovic

This study evaluated the effect of accelerated ageing on the tensile strength, elongation at break, hardness and Charpy impact strength in commercial PMMA denture base material modified with di-methyl itaconate (DMI) and di-n-butyl itaconate (DBI). The samples were prepared by modifying commercial formulation by addition of itaconates in the amounts of 2.5, 5, 7.5 and 10% by weight. After polymerization samples were characterized by FT-IR and DSC analysis while residual monomer content was determined by HPLC-UV. Accelerated ageing was performed at 70?C in water for periods of 7, 15 and 30 days. Tensile measurements were performed using Instron testing machine while the hardness of the polymerized samples was measured by Shore D method. The addition of itaconate significantly reduces the residual MMA. Even at the small amounts of added itaconates (2.5%) the residual MMA content was reduced by 50%. The increase of itaconate content in the system leads to the decrease of residual MMA. It has been found that the addition of di-n-alkyl itaconates decreases the tensile strength, hardness and Charpy impact strength and increases elongation at break. Samples modified with DMI had higher values of tensile strength, hardness and Charpy impact strength compared to the ones modified with DBI. This is explained by the fact that DBI has longer side chain compared to DMI. After accelerated ageing during a 30 days period the tensile strength decreased for all the investigated samples. The addition of DMI had no effect on the material ageing and the values for the tensile strength of all of the investigated samples decreased around 20%, while for the samples modified with DBI, the increase of the amount of DBI in the polymerized material leads to the higher decrease of the tensile strength after the complete accelerated ageing period od 30 days, aulthough after the first seven days of the accelerated ageing the values of hardness have increased for all of the investigated samples. Such behavior is explained as the result of the polymer chain relaxation. The values of Charpy impact strength decreased after accelerated ageing. The amount of added DMI have no affect on the decrease of Charpy impact strength after accelerated ageing, the decrease was similar as for pure PMMA. The decrease of Charpy impact strength increased as the amount of added DBI increases.


2021 ◽  
Vol 11 (12) ◽  
pp. 5317
Author(s):  
Rafał Malinowski ◽  
Aneta Raszkowska-Kaczor ◽  
Krzysztof Moraczewski ◽  
Wojciech Głuszewski ◽  
Volodymyr Krasinskyi ◽  
...  

The need for the development of new biodegradable materials and modification of the properties the current ones possess has essentially increased in recent years. The aim of this study was the comparison of changes occurring in poly(ε-caprolactone) (PCL) due to its modification by high-energy electron beam derived from a linear electron accelerator, as well as the addition of natural fibers in the form of cut hemp fibers. Changes to the fibers structure in the obtained composites and the geometrical surface structure of sample fractures with the use of scanning electron microscopy were investigated. Moreover, the mechanical properties were examined, including tensile strength, elongation at break, flexural modulus and impact strength of the modified PCL. It was found that PCL, modified with hemp fibers and/or electron radiation, exhibited enhanced flexural modulus but the elongation at break and impact strength decreased. Depending on the electron radiation dose and the hemp fibers content, tensile strength decreased or increased. It was also found that hemp fibers caused greater changes to the mechanical properties of PCL than electron radiation. The prepared composites exhibited uniform distribution of the dispersed phase in the polymer matrix and adequate adhesion at the interface between the two components.


BioResources ◽  
2010 ◽  
Vol 5 (3) ◽  
pp. 1618-1625
Author(s):  
M. Alamgir Kabir ◽  
M. Monimul Huque ◽  
M. Rabiul Islam ◽  
Andrzej K. Bledzki

Raw jute fiber was treated with o-hydroxybenzenediazonium salt (o-HBDS) in alkaline media. Raw and modified jute fiber were used to prepare composites by mixing with polypropylene (PP) plastic in different weight fractions (20, 25, 30, and 35%) of jute fiber. The mechanical properties except elongation at break of o-HBDS-treated (in alkaline medium) jute fiber-PP composite were higher than those of PP alone, raw jute fiber-PP composites, and alkali-treated jute fiber-PP composites. The elongation at break of treated jute-PP composite decreased to a large extent as compared to that of PP. The increase of tensile strength, tensile modulus, flexural strength, flexural modulus, and Charpy impact strength were found to be exceptionally high (in some cases ~200%) as compared to those of literature values.


2008 ◽  
Vol 74 (742) ◽  
pp. 915-916
Author(s):  
Yoshihiko HANGAI ◽  
Soichiro KITAHARA ◽  
Kenji SATO ◽  
Osamu KUWAZURU ◽  
Takao UTSUNOMIYA ◽  
...  

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