scholarly journals Transparent PC/PMMA Blends Via Reactive Compatibilization in a Twin-Screw Extruder

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2070 ◽  
Author(s):  
Tobias Bubmann ◽  
Andreas Seidel ◽  
Volker Altstädt

The effect of different catalysts on reactive compatibilization of 50/50 polycarbonate (PC)/polymethylmethacrylate (PMMA) blends achieved via transesterification that occurs during compounding in a twin-screw extruder was investigated on a phenomenological (optical and mechanical properties), mesoscopic (phase morphology), and molecular level (PC-graft(g)-PMMA-copolymer formation and polymer molecular weight degradation). Formation of PC-(g)-PMMA-copolymer by transesterification resulting in transparent mono-phase PC/PMMA blends with obviously improved compatibility of the two polymer constituents requires use of a suitable catalyst. As a side-effect, PC-(g)-PMMA-copolymer formation by transesterification is always accompanied by a significant simultaneous decomposition of the molecular weight (Mw) of the PC. For the first time, a colorless, transparent (mono-phase) PC/PMMA 50/50 blend was achieved by a twin-screw extrusion process that can be easily transferred into industrial scale. To achieve this milestone, 0.05 wt% of a weakly acidic phosphonium salt catalyst had to be applied. As a result of the decrease in Mw of the PC, the mechanical properties (e.g., tensile strain at break and impact strength) of the obtained blends were significantly deteriorated rather than improved as targeted by the polymer compatibilization; therefore, the produced transparent PC/PMMA blends are considered not yet technically suitable for any industrial applications. Different manufacturing process strategies that do not inherently result in PC degradation as a side effect of PC-graft(g)-PMMA-copolymer formation have to be developed to potentially achieve transparent PC/PMMA blends with a useful balance of properties. Based on the experimental observations of this study, a new mechanism of the transesterification reaction occurring during reactive compounding of PC and PMMA in the presence of the effective catalysts is proposed.

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1058
Author(s):  
Hikaru Okubo ◽  
Haruka Kaneyasu ◽  
Tetsuya Kimura ◽  
Patchiya Phanthong ◽  
Shigeru Yao

Each year, increasing amounts of plastic waste are generated, causing environmental pollution and resource loss. Recycling is a solution, but recycled plastics often have inferior mechanical properties to virgin plastics. However, studies have shown that holding polymers in the melt state before extrusion can restore the mechanical properties; thus, we propose a twin-screw extruder with a molten resin reservoir (MSR), a cavity between the screw zone and twin-screw extruder discharge, which retains molten polymer after mixing in the twin-screw zone, thus influencing the polymer properties. Re-extruded recycled polyethylene (RPE) pellets were produced, and the tensile properties and microstructure of virgin polyethylene (PE), unextruded RPE, and re-extruded RPE moldings prepared with and without the MSR were evaluated. Crucially, the elongation at break of the MSR-extruded RPE molding was seven times higher than that of the original RPE molding, and the Young’s modulus of the MSR-extruded RPE molding was comparable to that of the virgin PE molding. Both the MSR-extruded RPE and virgin PE moldings contained similar striped lamellae. Thus, MSR re-extrusion improved the mechanical performance of recycled polymers by optimizing the microstructure. The use of MSRs will facilitate the reuse of waste plastics as value-added materials having a wide range of industrial applications.


2021 ◽  
pp. 108201322110692
Author(s):  
Nispa Seetapan ◽  
Bootsrapa Leelawat ◽  
Nattawut Limparyoon ◽  
Rattana Yooberg

Rice noodles have been manufactured in the food industry using different extrusion methods, such as traditional and modern extrusions, which affect the noodle structure and qualities. Therefore, the effects of the extrusion process on qualities of rice noodles using the same blend of rice flour and crosslinked starch were evaluated. In this study, a capillary rheometer was used as an alternative approach to simulate the traditional extrusion method in which the noodles are obtained by continuously pressing the pregelatinized noodle dough through a die. For modern extrusion, a twin-screw extruder was employed to obtain the noodles in a one-step process. The optimal range of moisture content used in the formulation was studied. Upon cooking, the noodles showed a decrease in cooking time and cooking loss with increasing moisture content in the formulation. All cooked noodles showed comparable tensile strength, but those extruded by a twin-screw extruder had substantially greater elongation. Scanning electron micrographs revealed that the noodles prepared using the extruder had a denser starch matrix, while those obtained from a capillary rheometer showed the aggregation of starch fragments relevant to the existence of starch gelatinization endotherm from differential scanning calorimetry. This indicated that the extrusion process using the twin-screw extruder provided a more uniform starch transformation, i.e., more starch granule disruption and gelatinization, thus giving the noodles a more coherent structure and better extensibility after cooking. The obtained results suggested that different thermomechanical processes used in the noodle industry gave the extruded rice noodles different qualities respective to their different microstructures.


RSC Advances ◽  
2019 ◽  
Vol 9 (41) ◽  
pp. 23994-24002 ◽  
Author(s):  
Lucheng Qi ◽  
Lei Wu ◽  
Ren He ◽  
Hui Cheng ◽  
Boping Liu ◽  
...  

Blends of polypropylene (PP) and ultra-high molecular weight polyethylene (UHMWPE) with elastomer-olefin block copolymers (OBC) were prepared using an ultrasonic twin-screw extruder, and their mechanical and rheological properties were investigated.


2015 ◽  
Vol 1119 ◽  
pp. 283-287
Author(s):  
Sarit Liprapan ◽  
Thumnoon Nhujak ◽  
Pranut Potiyaraj

The objective of this study is to prepare α-cellulose reinforced poly (butylene succinate) composites (PBS/α-cellulose). The effect of amount α-cellulose on the mechanical properties of the composites was investigated. To improve interfacial interaction between PBS and α-cellulose, glycidyl methacrylate grafted poly (butylene succinate) (PBS-g-GMA) was used as a compatibilizer. Mechanical properties of PBS composites prepared by using a twin-screw extruder were investigated. The mechanical properties of PBS/α-cellulose decreased due to the agglomeration of α-cellulose. Nevertheless, tensile strength, Young’s modulus and flexural strength of PBS composites were improved after the incorporation of PBS-g-GMA. The optimum loading of PBS-g-GMA and α-cellulose in the PBS was found to be 5 and 6 phr.


2013 ◽  
Vol 561 ◽  
pp. 326-330
Author(s):  
Lei Guo ◽  
Qing Kun Liu ◽  
Chuan Sheng Wang

This paper uses a new twin-screw extruder for regeneration of waste tire crumb rubber, discusses the influence of screw speed and reaction temperature on the physical and mechanical properties of reclaimed rubber. Experimental results show that different screw speed and reaction temperature has a great impact on the physical and mechanical properties of the reclaimed rubber. When controls screw speed in the 60 ~ 90 r / min, reaction temperature at 170 to 210°C,the regeneration effect is the best. At this time, the physical and mechanical properties of reclaimed rubber, such as tensile strength, tear strength and elongation at break rate, is the best.


2022 ◽  
Author(s):  
A.M. Kuzmin

Abstract. The article discusses the possibility of obtaining biodegradable films based on polyolefins and beet pulp by the extrusion method. Biodegradable composites of two mixes with 15% and 25% beet pulp content have been obtained. Compounding was carried out on a twin-screw extruder, and then samples of biodegradable films were obtained by cast film extrusion. The influence of the vegetable filler particles’ orientation on the composites mechanical properties has been studied. It has been shown that composites mechanical properties significantly increase in the direction of polymer melt stretching.


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