NANO SILVER APPLICATION IN ANTIBACTERIAL AND ANTI-STATIC FABRIC

The results of investigating the antistatic and electrical properties of nano-coated coatings have been presented. The antistatic performance of the material is essential not only for safety, but also to prevent dirt attraction from affecting the electric field distribution in the high voltage insulation system. The polymer coating supplemented with silver and silica nanoparticles was examined by charge decay measurements after arc discharge. The charge decay time varied significantly between nanocoatings while the volume and surface resistivity of all tested coatings did not show significant differences. Polyester coatings dissipate heat quite well than polyesterimide because of its structure and permittivity. It was found that the surface charge discharge was better for coatings with nano silver while the nanosilica-modified coatings showed poor antistatic properties; The charge decay time is four orders of magnitude longer than that of the unmodified coatings. The barrier properties of nanosilica can be harmful to charge decay.

Vải nano bạc chống tĩnh điện

(NanoCMM Technology)

Customers who need 15000 ppm nano silver material for textile use, please contact Hotline 0378.622.740 – 098.435.9664

INTRODUCTION

Polymer nanocomposites, obtained by mixing polymers and nanofillers (i.e. particles with at least one size smaller than 100 nanometers), offer new opportunities for polymer nanocomposites in engineering. The technique exhibits beneficial electrical, thermal, mechanical, and barrier properties [1–8 ]. In this paper, research results on some electrical properties of polyester and poly esterimide coatings doped with low number of nanoparticles are presented. The issue is how the addition of metallic and non-metallic nanoparticles affects the antistatic properties of the coating. Antistatic performance testing is not required for these types of insulating coatings but it can be essential not only for safety and to prevent dust absorption but also for possible effect on distribution. electric field in high voltage insulation system.

The suitability of a material to avoid problems caused by static electricity is usually assessed by the resistivity value. Several works have shown that there is no relationship between surface resistivity and static charge dissipation [9]. Studies have shown that arc discharge gives results similar to a charge decay measurement and that three-dimensional charging after arc charging can be used to evaluate antistatic properties.

Experiment

Sample

Nanocoatings are prepared on the basis of two polymers, polyester (PK) and standard polyesterimide (T) and two types of nano-additives, silver nanoparticles and silica. The nanoparticle size is less than 100 nm and the silica nanoparticle is about 10 nm. The amount of nanosilver and nanosilica incorporated into the coating was 1.3% and 1.5%, respectively, by weight. A specially developed dispersion method was used to obtain nanocomposites. Automakers intend to patent that method in the near future. Two types of nano-filled test specimens have been prepared: for strength testing in the form of polymer coated steel plates and for antistatic property testing in the form of molded pads.

Measure

The antistatic and resistivity properties of nanoadditive modified polymer coatings were investigated by charge decay measurements after arc discharge, using the JCI 155 instrument manufactured by John Chubb Instrumentation export.

The main idea of electrostatic self-radiation on a material is to create an array of charges on the surface and measure the rate at which the charge decays generated. The antistatic measurement method used is unique and allows measurement of the ability to dissipate static charges from the surface. The schematic drawing of the measuring device is shown in Figure 1.

Figure 1 Diagram of the device to measure the antistatic effect of nano silver

The JCI 155v5 Charge Attenuation Tester measures surface voltage and it is mounted on the JCI 176 Charge Sample Holder where the sample is placed during the measurement. Atmospheric conditions such as temperature and humidity can be controlled using the JCI 191 Controlled Humidity Test Chamber.

The arc discharge points are mounted on the moving plate, under the fast response field gauge. The fieldmeter measures the surface voltage as the plate moves away after the arcing. Exclusive fast-responsive field mill electrostatic field meter for fast, sensitive and stable surface potential measurement.

The response time is less than 10 ms and the charge decay time can be measured from less than 50 ms to many days. Surface voltage measurement should start as soon as possible, so the plate needs to be moved quickly out of the way after charge build-up.

The charge deposition device completely moves out of the field of view of the field meter in less than 20 ms. The corona discharge point cluster provides arc discharge voltage from 2 kV to 10 kV and arc duration from 10 ms to 2 s.

In this paper sample is charged using positive and negative arc voltages of 5 kV for 20 ms. The software provides the opportunity to measure the average initial voltage developed by the charge build-up and record charge decay curves [10]. After calibration, the error of the measurements is less than 5%. There are two criteria for judging a material’s ability to dissipate static charges from its surface:

  • criterion 1 / e – decay time is measured to 1 / e (about 37%) of the initial peak voltage (Figure 2);
  • criterion 10% – decay time is measured to 10% of the initial peak voltage (Figure 2).

A simple acceptance test criterion that the time decay should be:

  • less than half a second in criterion 1/e (abbreviation of peak voltage about 37%);
  • less than 2 seconds in the 10% criterion (initial peak voltage to 10%).

Figure 2. Example charge decay time results for anode

Ngoài ra, đối với các lớp phủ tinh khiết và phủ nano, điện trở suất điện dưới điện áp thử nghiệm một chiều được xác định theo IEC 60093 ở nhiệt độ môi trường. Cuộc điều tra cũng được thực hiện ở nhiệt độ cao, gần với độ bền nhiệt dự kiến ​​của các lớp phủ thử nghiệm (180 ◦C). Thể tích và điện trở suất bề mặt được đo sau 1 min sử dụng cách sắp xếp ba điện cực. Điện áp thử nghiệm áp dụng là 100 V và các phép đo được thực hiện sau một phút điện khí hóa.

Test results

Antistatic properties of nano silver and nano silica

Figures 3 and 4 present the decay characteristics of surface voltage versus time for purification and modification with nanosilver and nanosilica PK coatings after negative and positive polarization, respectively. The charge decay time varied significantly between nano-filled coatings.

Figure 3. Decay of surface voltage versus time for AgNPs coating

Figure 4. Surface voltage versus time decay for AgNP coating

The surface charge discharge was better for coatings with silver nanoparticles, while the nanosilica-modified coatings showed poor antistatic properties. Two types of polymer samples, polyester PK and polyesterimide T with and without silica nanoparticles are compared in Figure 5. It can be noted that polyester disperses rather better than polyesterimide, probably because of its lower nominal electrical permittivity and structure. chemical (aromatic unsaturated polyester, no imide bonds). Deep traps on the polyesterimide surface are thought to cause difficulty in moving charges into large volumes or along the surface [11].

Figure 5. Decay of surface voltage versus time for pure and modified PK and T coatings with nano silver and nano silica

It was found that the surface had better charge dissipation for the coating with 1.3% silver nanoparticles (especially for the 10% criterion) while the nanosilica-modified coating showed good properties. poor antistatic agent; charge decay time is about four orders of magnitude longer than that of the unmodified coatings (Table I). There is probably a significant influence of the barrier effect in the polymer nanoparticle interface. Although the barrier properties of nanosilica are beneficial for e.g. reducing water absorption and enhancing the partial discharge resistance of coatings, they can also be detrimental to charge decay. The total amount of charge transferred to the sample by negative arc discharge is significantly larger than that of the positive charge, and it may be the reason that the values of decay times are much longer for negative arcs (Table I ). The reason for that could be the fact that in a negative arc the total number of electrons can be much higher although the number of very high energy electrons may be lower when compared to a positive arc.

TABLE I Values of measured decay time constant (time from peak voltage to 1/e and 10% of this value) for pure and controlled polyester (PK) and polyesterimide (T) coatings tuned with nano silver and nano silica.

Nano silver coating resistivity

The volume and surface resistivity of the PK polyester coating with and without the nanocoating are presented in Table II. At ambient temperature, both the volume and surface resistivity increased by about an order of magnitude after adding a small amount of nanofilm-forming agent and some decreased at 180 ◦C compared with the pure coating.

Table 2. Volume and surface resistivity of polyester PK coatings with and without nanofilters at 23 ◦C and 180 ◦C.

At present, the electrical conduction mechanism affected by nanoadmixtures remains elusive. Naturally, a very small amount of nanosilver (1.3% by weight at high specific gravity of silver) does not allow the galvanic threshold to be reached. Other studies have also shown the development of resistivity at ambient temperature after adding metal nanoparticles. They have found that the capacitor network, formed by nanoparticles in the polymer, has an effect. uses an obvious Coulomb blockade, and the conductivity is clearly limited in the mixture [12].

Kết luận hiệu quả chống tĩnh điện của nano bạc và nano silica

Investigation of the antistatic properties of the nano-coatings showed that incorporating a very small amount of silver nanoparticles into the polymer coating could improve the surface charge escape capacity while the addition of nanosilica made significantly reduce the antistatic properties of the coating. It was also found that at room temperature, the volume and surface resistivity of polymers containing 1.3% nanoweight increased compared with neat polymers probably due to the Coulomb blockade effect. Our investigations have shown that there is no relationship between the surface resistivity of the samples and the ability to dissipate static charges.

Reference source: Antistatic Properties of Nanofilled Coatings

  1. Gornickaa,∗ , M. Mazurb , K. Sieradzkab , E. Prociowb and M. Lapinskib aElectrotechnical Institute, Wrocław Division of Electrotechnology and Materials Science M. Sklodowskiej-Curie 55/61, 50-369 Wrocław, Poland bFaculty of Microsystems Electronics and Photonics, Wrocław University of Technology Janiszewskiego 11/17, 50-372 Wrocław, Poland