Physical and chemical effects of ultrasound vibration on polymer melt in extrusion

Chen, Jinyao; Chen, Yingzi; Li, Huilin; Lai, Shih‐Yaw; Jow, Jinder

doi:10.1016/j.ultsonch.2009.05.005

Cited by 79 publications

(53 citation statements)

References 7 publications

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“…High intensity ultrasonic waves may cause adverse effects on the polymeric chains as a result of cavitation and the high temperature that can be reached inside the plasticizing chamber [23][24][25][26]. Thus, processing conditions (i.e.…”

Section: Resultsmentioning

confidence: 99%

Preparation of micro-molded exfoliated clay nanocomposites by means of ultrasonic technology

et al. 2014

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Ultrasound micro-molding technology has been tested as a new method to get polymer/clay nanocomposites. Biodegradable polylactide (PLA) and poly (nona-methylene azelate) (PE99) have been used as polymer matrices, whereas different silicate clays have been assayed. The new technology is able to get specimens without evidences of degradation during processing. Only the use of organo-modified clays could give rise to a slight molecular weight decrease when the poly (alkylene dicarboxylate) sample was considered. Ultrasonic micro-molding has revealed effective to get directly nanocomposites with the final form required for a selected application, a homogeneous clay distribution up to a load of 6 wt-% and more interestingly exfoliated structures without being necessary the use of a compatibilizer agent between the organic polymer and the inorganic silicate clay. Transmission electron micrographs and X-ray diffraction profiles revealed exfoliated structure when N757, C20A, C25A, and N848 clays were employed.; Crystallization behavior of exfoliated PLA nanocomposites was highly peculiar since clay particles had an antinucleating effect that decreased the overall crystallization rate respect to the neat polymer. In addition, the incorporation of layers into growing spherulites increased the crystal growth rate. A typical crystallization effect was on the contrary observed for nanocomposites derived from the poly (alkylene dicarboxylate) sample.Peer ReviewedPostprint (published version

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Section: Resultsmentioning

confidence: 99%

Preparation of micro-molded exfoliated clay nanocomposites by means of ultrasonic technology

et al. 2014

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“…That is because the melt feeding resistance increases and more compression pressure is correspondingly required. When the ultrasound duration time is prolonged, the viscosity and elasticity of the polymer melt decrease, while the temperature and inner stress of the melt are homogenized; therefore, micro-plastic parts with a better quality are achieved (Chen et al, 2010;Jiang et al, 2012;Liang et al, 2014).…”

Section: Application Of Micro-hole Array Pcb Inserts In a Micro-ultramentioning

confidence: 99%

Mechanical drilling of PCB micro hole and its application in micro ultrasonic powder molding

Liang

Fu³

et al. 2015

Circuit World

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Purpose – This paper aims to present the main factors affecting the mechanical drilling of the printed circuit board (PCB for short) micro-holes and method of micro-ultrasonic powder molding (micro-UPM for short) by utilizing PCB micro-hole array. Design/methodology/approach – To optimize the drilling process, the paper proposes the on-line monitoring methods for the drilling process including drilling force, drilling temperature, high-speed photography and vibration signals. Taking 0.10 and 0.15 mm micro-drilling as examples, the paper analyzes the drilling process of ultra-small micro-holes. Finally, by taking the PCBs with 0.10 and 0.15 mm micro-hole arrays as the micro-cavity inserts, utilizing ultra-high-molecule weight polyethylene powder with the average particle size of about 150 μm as raw material, two sizes of micro-cylinder array polymer parts are fabricated through micro-UPM process. Findings – PCB micro-cavity inserts with micro-hole arrays fabricated by mechanical drilling has the advantages of low costs, high efficiency and good consistency. Taking 0.10 and 0.15 mm micro-drilling as examples, it is found that the both measured apertures are about 10.0 μm more than the diameter of the micro-drill bits on average. The average diameter of the micro-cylinders by micro-UPM process is smaller than that of the micro-hole with the same specification, while the value of the roughness of the cylinder surface is more than that of the hole-wall surface with the same specification. Originality/value – This paper describes the challenges and the developments of mechanical drilling and by using PCB micro-cavity inserts with micro-hole arrays fabricated by mechanical drilling, two different micro-cylinder array polymer parts are successfully made and thus the application area of PCB micro-drilling is broadened.

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“…When the ultrasonic plasticizing time was prolonged, the viscosity and the elasticity of the polymer melt decreased, and the temperature and the inner stress of the material were homogenized. Therefore, the quality of the plastic parts was improved (Chen et al, 2010;Jiang et al, 2012).…”

Section: Molding Process Parametersmentioning

confidence: 99%

Micro UHMW‐PE column array molded by the utilization of PCB as mold insert

Liang

et al. 2013

Circuit World

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Purpose -The purpose of this paper is to present a method for ultrasonically molding polymer powder in a micro plastic part mold. In the method, a printed circuit board (PCB) in which micro-hole arrays are drilled is used as a micro cavity insert. With the utilization of ultrasonic vibration, the polymer powder, which is prefilled and compacted in a micro cavity, mutually generates great sliding friction heat so as to be rapidly plasticized and molded. Design/methodology/approach -Micro carbide drill bits of which the diameters are 100.0 mm, 150.0 mm and 200.0 mm, respectively, are used for drilling the PCB to form a micro-hole array insert. Next, two kinds of various ultra-high molecule weight polyethylene (UHMW-PE) powder with various grain diameters are directly filled into a charging barrel and a mold cavity with the micro-hole array insert. Proper process parameters are set on ultrasonic plasticizing and molding equipment so that a molding test can be performed. The melt of UHMW-PE can be rapidly filled into the cavity. Finally, micro-column array plastic parts are successfully prepared. Findings -The micro-hole array PCB is a mold insert which is quite applicable for the ultrasonic molding of the powder in the mold. When a molding material is the coarse UHMW-PE powder with the grain diameter of about 350 mm, the diameter replication rates of the micro-column array plastic parts become good in order with the increased micro-hole diameter of the PCB. When the fine UHMW-PE powder with the grain diameter of about 80 mm is adopted, the diameter replication rates of the micro-column array plastic parts become good in order with the decreased micro-hole diameter of the PCB. Originality/value -In this paper, the micro-column array plastic parts with good replicability are successfully prepared by a technique for ultrasonically plasticizing and molding in the cavity. The technique can be applied to the fields of medical treatment, communication, optics, chemistry and so on, such as biological micro needle arrays, micro biological chips, optical memories, and micro chemical reaction chips.

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Physical and chemical effects of ultrasound vibration on polymer melt in extrusion

Cited by 79 publications

References 7 publications

Preparation of micro-molded exfoliated clay nanocomposites by means of ultrasonic technology

Preparation of micro-molded exfoliated clay nanocomposites by means of ultrasonic technology

Mechanical drilling of PCB micro hole and its application in micro ultrasonic powder molding

Micro UHMW‐PE column array molded by the utilization of PCB as mold insert

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