مروری بر خواص و تهیه پلیمرهای سلولی پیزوالکتریک

نوع مقاله: مروری

نویسندگان

1 تهران، دانشگاه صنعتی امیرکبیر، واحد ماهشهر، کد پستی 6351713178

2 تهران، پژوهشگاه پلیمر و پتروشیمی ایران، پژوهشکده فرایند، صندوق پستی 112-14975

10.22063/jipst.2020.1717

چکیده

پیزوالکتریسیته قابلیتی است که طی آن مواد ویژه‌ای می‌توانند انرژی‌ مکانیکی را به الکتریکی و برعکس تبدیل کنند. افرون بر سرامیک‌ها (مانند PZT) و پلیمرهای قطبی (PVDF و کوپلیمرهای آن)، در دو دهه‌ اخیر پلیمرهای سلولی غیرقطبی نیز به‌دلیل داشتن قیمت مناسب، سبکی، انعطاف‌پذیری و ضریب پیزوالکتریک (d33)، بسیار مورد توجه قرار گرفته‌اند. این پلیمرها برای کاربردهای مختلف همچون در جاذب‌های انرژی، حسگرها و در زمیته‌ علوم پزشکی به‌کار گرفته می‌شوند. پلی‌پروپیلن (PP)، پلی‌اتیلن ترفتالات (PET)، پلی‌اتیلن نفتالات (PEN)، پلی‌اتیلن (PE) و پلی‌الفین‌های حلقوی (COP) و مواد گرمانرم، ضریب پیزوالکتریک زیادی نشان می‌دهند. با قرارگیری این فیلم‌های سلولی در میدان الکتریکی قوی (تخلیه هاله یا میان دو الکترود) و در مجاورت گاز یون‌کننده، گاز به‌وسیله میدان الکتریکی یون می‌شود، درون سلول‌ها باقی می‌ماند و گشتاور دوقطبی نشان می‌دهد. به‌دلیل رفتار شبه‌پیزوالکتریک این مواد، آن‌ها را پیزوالکترت و به خواصی که نشان می‌دهند، فروالکتریسیته می‌گویند. عامل‌های مهمی همچون ساختار سلول‌ها (شکل‌شناسی، اندازه و چگالی)، نوع گاز یون‌‌کننده و مدول یانگ بر ضریب پیزوالکتریک اثر مستقیم می‌گذارند. افزون بر این، عمل‌اوری‌های پس‌فراورشی همچون فرایندهای شیمیایی و کشش نیز خواص پیزوالکتریک را بهبود می‌دهند. پلی‌پروپیلن یکی از پلیمرهای سلولی پرکاربرد در زمینه پیزوالکتریک‌هاست که به‌دلیل داشتن ویژگی‌هایی مانند قیمت مناسب، مقاومت خستگی و حبس شارژ خوب در سلول‌ها زمینه مطالعه را برای سایر پلیمرها فراهم کرده است. در این مقاله، پیشرفت‌های اخیر در زمینه بهبود ضریب پیزوالکتریک و فرایند کار بحث شده است. اثر عامل‌های مختلف همچون استحکام شکست الکتریکی گازهای مختلف، مدول یانگ، دمای کارکرد پلیمر و افزودنی‌ها بر پیزوالکتریسیته در پلیمرهای سلولی بررسی و مرور شده است.

کلیدواژه‌ها


عنوان مقاله [English]

An Overview on Piezoelectric Cellular Polymers: Properties and Preparation

نویسندگان [English]

  • Sorena Azidhak 1
  • Ali Akber Yousefi 2
  • Ahmad Reza Taghizadeh 1
  • Ali Akbar Zarei 1
1 Amirkabir University of Technology, Mahshahr Campus, Postal Code 6351713178 , Mahshahr, Iran
2 Department of Plastics, Faculty of Processing, Iran Polymer and Petrochemical Institute, P.O. Box: 14975-112, Tehran, Iran
چکیده [English]

Piezoelectricity can be described as a capability of some particular materials which convert mechanical energy to electrical and vice versa. In addition to ceramics (such as PZT) and polar polymers (PVDF and its copolymers), non-polar cellular polymers have received much attention in the last two decades due to their reasonable price, light weight, flexibility, and piezoelectric coefficient (d33). These polymers are used for a variety of applications, such as energy absorbers, sensors, and the medical sciences. PP, PET, PEN, PE and COP are thermoplastic materials which show high piezoelectric coefficient. By placing these cellular films in a strong electric field (corona discharge or between two electrodes) and in the vicinity of ionizing gas, the gas is ionized by electric field and remains inside the cells, indicating a bipolar moment. Due to the quasi-piezoelectric behavior of these materials, they are called ‘piezoelectrets’ and their properties are called ‘ferroelectricity’. Important factors such as cell structure (morphology, size and density), ionizing gas type, and Young's modulus have direct effect on the piezoelectric coefficient. Furthermore, some post-processing treatments such as chemical and stretching processes improve the piezoelectric properties. Polypropylene is one of the most widely used cellular polymers in the field of piezoelectrics due to features such as reasonable price, good fatigue resistance, and good charge trapping in cells, which has provided a study platform for other polymers. In this review article, we discuss on recent developments in improving piezoelectric coefficient and the work process. The effects of different parameters like electrical breakdown strength of various gases, additives, servicing temperature of polymers and Young's modulus on piezoelectricity in cellular polymers are investigated.

کلیدواژه‌ها [English]

  • piezoelectricity
  • cellular polymers
  • ferroelectret
  • Polypropylene
  • piezoelectric coefficient
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