Preparation and research of graphene conductive powder coating

Functional powder coating is an important direction of the development of powder coating, such as conductive powder coating, it is low-cost, simple construction process, in anti-corrosion, electromagnetic shielding, anti-static and other fields have broad application prospects. At present, conductive coatings can be divided into 2 categories: (1) structural conductive coatings, such as conductive polymer polyphenylamine, such as this type of conductive coating conductivity is low, in the application environment easy to lose conductivity, processing difficult, high cost; System, carbon system, metal oxide system and other additives, its metal filler antioxidant, corrosion resistance is poor, carbon system conductive filler has the color of too deep defects, metal oxide series production costs are high, high density, by its preparation of conductive coatings have certain limitations
.
, the development of new conductive coatings is of
.graphene permeability, high strength, high conductivity, can make the coating with anti-aging, scratch-resistant, conductive and other properties, and can extend the life of the coating film. Reich and other graphene as an auxiliary material added to acrylic coatings, prepared a coating resistance of 87.8 Ω
;
, graphene is added to the coating as a filler, which is large and costly, making it difficult to achieve industrial
.
development of graphene with low amount of graphene, low cost graphene conductive coating is imminent, and there is no graphene in powder coating application research
.technology is to adhere pearlescent or metal powder to the surface of the powder, so that the coating has a metal effect
.
This study will be graphene sheet to the surface of the powder coating, because graphene sheet layer thin, low density, in the curing process, graphene sheet can be migrated to the surface of the coating, cured into a film can be prepared to obtain a conductive graphene powder coating
.
The coating preparation method is simple, the resistivity is small, the graphene addition is low, and the method has universality, which has a certain guiding significance for the preparation of high hardness, scratch resistance and other graphene coatings
1
Experimental part 1.1
main raw materialspolyester resin: industrial grade, DSM; graphene: industrial grade, Ningbo Merci Technology Co., Ltd.; isocyanate triglycerides (TGIC): industrial grade, Changzhou City Niutang Chemical Plant Co., Ltd.; Leveling agents: industrial grade, Estron Corporation of the United States; Power booster: industrial grade, Shanghai Soo is Chemical Co., Ltd.; Bonding wax powder: industrial grade, Clariant; mobile additives: industrial grade, Germany Bick Chemical Co., Ltd.; Sulphate: industrial grade, Foshan Any billion nanomaterials Co., Ltd.; carbon black: industrial grade, Germany Created Degusai Company; Titanium white powder: industrial grade, Sichuan Longyu Titanium Co., Ltd.

China.1.2
Main InstrumentsDisperser: MB10, Lemet Henjul Mixing Systems, Germany; Twin Screw Melt Extruder: SLJ-25, Yantai Lingyu Powder Machinery Co., Ltd.; High-speed Shredder: ACM 02, Yantai Dragon Color New Materials Co., Ltd.; High-voltage electrostature spray gun: PEM-X1, Wagner Spray Equipment, Germany; Differential thermal scanner: Q20, TA Corporation of the United States; Infrared Spectrometer: Nicolet 380, Thermo Fiesel Corporation; Surface Resistance Tester: TRACK MODEL-100, Kunshan Henster Electronic Materials Co., Ltd.
.1.3
powder coating preparation 1.3.1
internal extrusion graphene powder coatingpolyester resin, curing agent, leveling agent, wetting agent, Pigments, etc. are prepared as mastercraft by Table 1, where Trail 1 does not add graphene, Trail 2 and Trail 3 add 0.3% and 1% graphene, respectively, to Trail 1
.
is squeezed out by melting and mixing, the flakes are cooled, then crushed and crushed, and then graded through a sieve to prepare the powder coating
.Table 1 In-squeeze legal graphene powder coating formula
1.3.2
Bonding legal preparation graphene powder coatingaccording to table 1 Trail 1 formula, polyester resin, curing Agents, leveling agents, moisturizers, pigments, etc. in accordance with a certain proportion of preparation into mastermission, after melting extruded mixed, pressure sheet cooling, and then after crushing and crushing, and then grading, screening to prepare powder coating base
.Mix the powder coating base and wax powder prepared above according to table 2 formula, place in the Bonding machine, heat up at a certain rate in the N 2 atmosphere, and add graphene with mass scores of 0.15% and 0.3% respectively after the temperature rises to 63 degrees C, keeping the temperature unchanged; After 2 min, turn on the cooling water switch, adjust the Bonding machine speed to cool it down, and when the temperature drops to 40 degrees C, add the flow aid and remove the Bonding powder coating for graphene powder coatings (Trail 4 and Trail 5)
with graphene content of 0.15% and 0.3%, respectively. Table 2 Bonding Legal Preparation Graphene Powder Coating Formula
The process schematic of binding legally prepared graphene conductive coatings is shown in figure 1
.
diagram of the conductive graphene powder coating prepared by Bonding Legal System is 1.4
Preparation of the coating Sieve the graphene powder coating sample powder, take 100 g sample powder placed in the spray gun, spray the graphene powder coating on the aluminum plate, and then place it in the oven, bake 10 min at 200 degrees C, remove the sample to cool to room temperature
. 1.5
a small amount of powder coating tested and spectrometer (FT-IR) was used to visually signal its chemical
.
used a differential scan thermal instrument (DSC) to determine the degree of curing
. use the surface resistance tester to test the surface resistance of the coating
.
coating film thickness is tested by ISO 2360:2017, gloss (60 degrees) by ISO2813:2014, impact resistance is tested by ISO 6272-1:2002, and adhesion is tested by ISO 2409:2013
.
coating gelting time is tested by ISO 8130-6:2011, and the slope length is tested by ISO 8130-11:2011
. 2
results and discussion 2.1
Red Appearance Signs Infrared spectra of un cured Trail 1 to Trail 5 powder coatings are shown in figure 2
.
2 Infrared spectroscopy of each powder coating As can be seen from Figure 2, 3 433 cm-1 in trail 1 is the telescopic vibration absorption peak of OH; O's telescopic vibration absorption peak; 1 704 cm-1 is the characteristic absorption peak of the neighbor methyl; 1 268 cm-1 is the C-O asymmetric telescopic vibration in benzoate; these characteristic absorption peaks are mainly derived from polyester
in the formulation.
trail 2
adds 0.3% graphene to trail 1, a powder coating prepared by internal extrusion, and a C-O-C vibration absorption peak can be found at 1 101 cm-1, which is mainly derived from graphene; Trail 5 is based on trail 1 to add 0.3% graphene, through the Bonding legal system of powder coating, compared to trail2, the C-O-C vibration absorption peak in trail 5 is very strong, indicating that compared to the internal extrusion method, through Bonding technology is easier to make graphene on the base surface
. 2.2 DSC
the DSC curve the powder coating as shown in figure 3
.
3 DSC curves for each powder coating As can be seen from Figure 3, trail 1 does not add graphene, the glass transition temperature of its powder is 60.99 degrees C, a curing reaction begins at 152 degrees C, and the maximum reaction temperature occurs at 207 degrees C
.
trail 3 and trail 5 add graphene, the glass transition temperature, starting temperature, and The reaction temperature, and the maximum reaction temperature did not change dramatically
.
can be seen that the addition of graphene has no effect on the curing of powder coatings
. 2.3
Performance Test for Graphene Powder Coatings 2.3.1
Conductive Performance Test Conductive Tests for each coating are shown in
. 3 Conductive Experiments on Graphene Powder Coatings
As can be known from Table 3, the surface resistance of the trail 1 coating is 1012 s, and the surface resistance of the trail 2 coating (insisting method, 0.3% graphene content) is still After increasing the amount of graphene used for 1012 ohms, the surface resistance of the trail 3 coating (internal extrusion, 1% graphene content) is reduced to 108 s, at which point the coating has the ability to conduct static electricity, which can effectively prevent the safety hazards caused by static electricity
.
the surface resistance of the trail 4 coating (Bonding, 0.15% graphene content) is 107 s, while the surface resistance of trail 5 coating (Bonding method, 0.3% graphene content) is reduced to 106 s
.
result, when graphene usage is also 0.3%, the resistivity of the internal extrusive coating is 1012 s, while the Bonding method can be reduced to 106 s
.
Bonding technology can greatly reduce the amount of graphene in electrostectrective coatings, reduce the cost
. According to conductivity theory, in a coating system, electrons migrate in gaps between conductive particles that do not come into contact with each other, connect them into chains, and electrons move through chains to produce conductive phenomena, or under the conditions of field-induced emission, electrons migrate in gaps in conductive particles that do not come into contact with each other, producing a conductive effect of
.
the two theories suggest that the number of conductive particles in the substation should have a certain value and that the particles should be very small
.
when graphene is not added, trail 1 does not contain conductive substances and therefore exhibits insulation properties
.
graphene is added to the powder coating through internal extrusion, will be completely dispersed in the substate, the amount of addition is 0.3%, graphene sheets are far apart from each other, not connected to the chain, resistance is large, does not have the electrostring function, and after the addition of 1%, the amount of graphene in the substation increased, electronic transmission channel formation, can achieve conductive characteristics
.
Graphene is added to the powder coating through Bonding, graphene sheet Bonding to the surface of the powder coating, in the curing process, graphene sheet can be migrated to the surface of the coating, cured into a film after graphene in the coating surface rich, stacked, forming a dense conductive layer, thus showing excellent conductivity
.
graphene rich in coating surface will have many effects on coating surface performance, we will discuss in a follow-up paper
. 2.3.2
Physical Performance Test controls each coating to test coating performance over the same film thickness range, and the test results are as shown in
. Table 4 Physical Properties of Each Powder Coating
Through collation experiments, it can be found that trail 1, trail 3 and trail 5 are gluing at 440 s, 467 s and 452 s, respectively, indicating that the addition of graphene has no effect on the curing of powder coatings
.
From Table
4
it can also be seen that after the addition of graphene on the basis of Trail 1, the gloss, cup convexity and adhesion of each graphene powder coating did not change much, but the impact resistance of the coating was reduced to a certain extent, mainly because graphene is thin, there is a gap between the sheet and the piece, with a certain oil absorption value of
.
As can be seen from the slope length of the coating, Trail 1 has a longer slope length than other formulations, indicating that when graphene is added, its large oil absorption results in a larger viscosity of the system, a poor wetting of the substrate, and because it is thin The shape of the whole coating has played a role in physical partitioning, so that the crosslink density of the whole system is lower, so the impact resistance is affected to a certain extent, but the impact resistance results of the series of coatings can meet the general application requirements, and therefore does not affect the normal application of the coating
. <b。