Influence of particle size of isotactic polypropylene (iPP) on barrier property against agglomeration of homogenized microcrystalline cellulose (HMCC) in iPP/HMCC composites

2018 ◽  
Vol 38 (3) ◽  
pp. 213-222 ◽  
Author(s):  
Ning Xu ◽  
Enyong Ding ◽  
Feng Xue

AbstractIsotactic polypropylene (iPP) powders were treated by a colloid mill for different times to obtain a series of particle sizes ranging from 682 μm to 89 μm. The relative crystallinity degree index (Xc, %) calculated by X-ray diffraction, and the initial degradation temperature measured by thermogravimetry, were all reduced after the milling process, which revealed that the structure of iPP molecular chains was destroyed during the powerful shearing and friction action. Furthermore, the increasing melt flow rate (MFR) index indicated that the molecular weight of iPP had reduced during the mechanical treatment. Scanning electron micrographs showed the inevitable agglomeration of homogenized microcrystalline cellulose (HMCC) fibers after being dried directly without iPP powders. However, the addition of achieved superfine iPP powders presented a good barrier property against the agglomeration phenomenon and consequent improvement in mechanical performance of the iPP/HMCC composites.

2013 ◽  
Vol 33 (3) ◽  
pp. 229-238 ◽  
Author(s):  
Ismaeel M. Alwaan ◽  
Azman Hassan

Abstract The effects on the thermal, morphological, and crystallinity properties of the different loadings of magnesium oxide (MgO) blended with 10% rubbers [9:1 natural rubber (NR)/epoxidized NR] and metallocene linear low-density polyethylene (mLLDPE) in the presence of N,N-m-phenylenebismaleimide (HVA-2) compatibilizer were investigated. Fourier transform infrared spectroscopy showed that the epoxy and double-bond groups were absent in the blends. The crystallinity degree of mLLDPE composites were determined based on the results of differential scanning calorimetry. The crystallinity of the blends was continuously increased by the loading of MgO compared with blend of 0 phr MgO. Based on thermogravimetric analysis, the degradation temperature of NR in the blends with MgO is significantly enhanced compared with a pure NR and 0 phr MgO blend. The observations of the scanning electron micrographs indicate that the HVA-2 had caused a cross-linking reaction in the rubber phase and the domains of the MgO are separated from the continuous phase (mLLDPE).


Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1472 ◽  
Author(s):  
Oskars Platnieks ◽  
Sergejs Gaidukovs ◽  
Anda Barkane ◽  
Aleksandrs Sereda ◽  
Gerda Gaidukova ◽  
...  

Biodegradable polymer composites from renewable resources are the next-generation of wood-like materials and are crucial for the development of various industries to meet sustainability goals. Functional applications like packaging, medicine, automotive, construction and sustainable housing are just some that would greatly benefit. Some of the existing industries, like wood plastic composites, already encompass given examples but are dominated by fossil-based polymers that are unsustainable. Thus, there is a background to bring a new perspective approach for the combination of microcrystalline cellulose (MCC) and nanofibrillated cellulose (NFC) fillers in bio-based poly (butylene succinate) matrix (PBS). MCC, NFC and MCC/NFC filler total loading at 40 wt % was used to obtain more insights for wood-like composite applications. The ability to tailor the biodegradable characteristics and the mechanical properties of PBS composites is indispensable for extended applications. Five compositions have been prepared with MCC and NFC fillers using melt blending approach. Young’s modulus in tensile test mode and storage modulus at 20 °C in thermo-mechanical analysis have increased about two-fold. Thermal degradation temperature was increased by approximately 60 °C compared to MCC and NFC. Additionally, to estimate the compatibility of the components and morphology of the composite’s SEM analysis was performed for fractured surfaces. The contact angle measurements testified the developed matrix interphase. Differential scanning calorimetry evidenced the trans-crystallization of the polymer after filler incorporation; the crystallization temperature shifted to the higher temperature region. The MCC has a stronger effect on the crystallinity degree than NFC filler. PBS disintegrated under composting conditions in a period of 75 days. The NFC/MCC addition facilitated the specimens’ decomposition rate up to 60 days


Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1383
Author(s):  
Jerzy Korol ◽  
Aleksander Hejna ◽  
Klaudiusz Wypiór ◽  
Krzysztof Mijalski ◽  
Ewelina Chmielnicka

The recycling of plastics is currently one of the most significant industrial challenges. Due to the enormous amounts of plastic wastes generated by various industry branches, it is essential to look for potential methods for their utilization. In the presented work, we investigated the recycling potential of wastes originated from the agricultural films recycling line. Their structure and properties were analyzed, and they were modified with 2.5 wt % of commercially available compatibilizers. The mechanical and thermal performance of modified wastes were evaluated by tensile tests, thermogravimetric analysis, and differential scanning calorimetry. It was found that incorporation of such a small amount of modifiers may overcome the drawbacks caused by the presence of impurities. The incorporation of maleic anhydride-grafted compounds enhanced the tensile strength of wastes by 13–25%. The use of more ductile compatibilizers—ethylene-vinyl acetate and paraffin increased the elongation at break by 55–64%. The presence of compatibilizers also reduced the stiffness of materials resulting from the presence of solid particles. It was particularly emphasized for styrene-ethylene-butadiene-styrene and ethylene-vinyl acetate copolymers, which caused up to a 20% drop of Young’s modulus. Such effects may facilitate the further applications of analyzed wastes, e.g., in polymer film production. Thermal performance was only slightly affected by compatibilization. It caused a slight reduction in polyethylene melting temperatures (up to 2.8 °C) and crystallinity degree (up to 16%). For more contaminated materials, the addition of compatibilizers caused a minor reduction in the decomposition onset (up to 6 °C). At the same time, for the waste after three washing cycles, thermal stability was improved. Moreover, depending on the desired properties and application, materials do not have to go through the whole recycling line, simplifying the process, reducing energy and water consumption. The presented results indicate that it is possible to efficiently use the materials, which do not have to undergo the whole recycling process. Despite the presence of impurities, they could be applied in the manufacturing of products which do not require exceptional mechanical performance.


2021 ◽  
Vol 288 ◽  
pp. 123053
Author(s):  
Saulo Rocha Ferreira ◽  
Neven Ukrainczyk ◽  
Keoma Defáveri do Carmo e Silva ◽  
Luiz Eduardo Silva ◽  
Eduardo Koenders

Author(s):  
Guilong Li ◽  
Shichang Du ◽  
Bo Wang ◽  
Jun Lv ◽  
Yafei Deng

Abstract In face milling process, the quality of surface texture is vital for mechanical performance of workpieces. The quality of surface texture, especially for waviness, is directly affected by tool marks, a commonly observed phenomenon in face milling. However, appropriate approaches for evaluation and modeling of tool marks are absent to date. Limited to the resolution as well as the efficiency of conventional measurement instruments, the height data of tool marks is hard to be entirely obtained, leading to valuable information omission. Besides, most existing models of tool marks are established for general workpieces with regular geometry and continuous surfaces. Since the cutter-workpiece engagement mode has a significant impact on the generation of tool marks, current models could be inaccurate or invalid when dealing with workpieces with discontinuous surfaces. To overcome this shortage, a novel approach is proposed in this paper, aimed at quality improvement of surface texture in face milling of workpieces with discontinuous surfaces. Firstly, the evaluation indexes for tool marks are defined based on the recently developed high definition metrology (HDM). Secondly, the physical modeling of tool marks is presented, taking the face milling mechanism into account. Thirdly, the physical-informed optimization model is developed to search for the optimal processing parameters for surface quality improvement. At last, the effectiveness of the proposed approach is verified by a face milling experiment on the engine blocks.


2017 ◽  
Vol 52 (5) ◽  
pp. 701-711 ◽  
Author(s):  
Danielle M Mariano ◽  
Daniela FS Freitas ◽  
Luis C Mendes

Nanocomposite based on polypropylene and octadecylamine-modified lamellar-zirconium phosphate (PP/nano-ZrPOct) was prepared by melt processing. The action of the nanofiller and screw speed on the properties were evaluated. SEM images revealed that at highest screw speed, the higher nano-ZrPOct dispersion was achieved. In WAXD diffractrograms, some nanofiller diffraction peaks disappeared and a new peak was observed at low angle. There was evidence of increase of thermal stability although only discrete increasing in initial degradation temperature has been noticed. Melting and crystallization temperatures were invariable but crystallinity degree was influenced with a decreasing behavior at highest screw speed. The results strongly evidenced that the intercalation of the PP chains inside the nano-ZrPOct galleries and some degree of delamination of the nanofiller platelets have been achieved.


2014 ◽  
Vol 608 ◽  
pp. 8-13 ◽  
Author(s):  
X. Spiliotis ◽  
K. Ntampegliotis ◽  
D. Kasiteropoulou ◽  
S. Lamprakopoulos ◽  
K. Lolos ◽  
...  

The mill scale (MS) waste is produced in steel industry during the milling process from the rapid oxidization of the hot iron products, and is mainly consisted of iron oxides (>95%). The aim of this work is to evaluate the utilization of MS (known in Greece as “kalamina”) as an admixture in clay bricks manufacturing by applying extrusion and sintering processes. For that purpose, specimens were formed from various clay/MS mixtures (up to 9 wt% MS) and then fired at different temperatures (up to 1100°C). Shrinkage and weight loss upon firing as well as density, porosity, bending strength and thermal conductivity of sintered specimens were determined and studied as a function of the % MS content and the firing temperature for optimization. The experimental results show that the incorporation of MS in clay bricks production is feasible, as an efficient secondary resource, thus turning waste from one industry into useful feedstock for another one. Specifically, the mechanical performance and thermal conductivity are not significantly affected with increasing the mineral admixture percentage and the sintering temperature.


BioResources ◽  
2018 ◽  
Vol 13 (3) ◽  
pp. 6238-6249
Author(s):  
A. M. Radzi ◽  
S. M. Sapuan ◽  
M. Jawaid ◽  
M. R. Mansor

The effect of sugar palm fiber (SPF) loading was studied relative to the mechanical properties of roselle (RF)/SPF/thermoplastic polyurethane (TPU) hybrid composites. RF/SPF/TPU hybrid composites were fabricated at different weight ratios (100:0, 75:25, 50:50, 25:75, and 0:100) by melt mixing and hot compression. The mechanical (tensile, flexural, and impact test) and morphological properties of tensile fractured samples were examined using a universal testing machine, impact machine, and scanning electron microscope. It was found that the hybridization of RF/SPF increased its impact strength corresponding to the increases in the SPF content of the composites. The tensile and flexural properties of the hybrid composites decreased due to poor interfacial bonding between the fiber and matrix. Scanning electron micrographs of the tensile fractured surface of the RF/SPF hybrid composites revealed fiber pullouts and poor adhesion bonding. In conclusion, the hybridization of SPF with RF/TPU composites enhanced its impact strength while decreasing the tensile and flexural strength.


2019 ◽  
Vol 7 (4.14) ◽  
pp. 339
Author(s):  
N. Samat ◽  
N. N. Ghazali ◽  
Z. Ahmad ◽  
F. Ali

In this study, the microcrystalline cellulose (MCC) was extracted via a non-acidic method from the oil palm empty fruit bunch (EFB) cellulose. The extraction was conducted through Ammonium Persulfate (APS) oxidation treatment, which was followed by the ball milling process. The effects of varied temperature levels from APS oxidation treatment (60, 80 and 90oC) and different milling time (1, 4 hours) were investigated. APS oxidation treatment at 90oC was found to produce the most optimum results. The size of the MCC was less than 20μm and had demonstrated the highest degree of crystallinity index and thermal stability. The high crystallinity index is associated with the removal of non-cellulosic components as seen from FTIR analysis, where a decrease was observed in the characteristic peak intensity of 1735 and 1510 cm-1. The milling time had also affected the formation of MCC. Although a relatively longer milling time had produced smaller MCC with narrow size distribution, it had, however, given rise to a slight adverse effect on the crystallinity index and thermal stability.              


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