Nghiên cứu tổ hợp vật liệu sơn chịu nhiệt trên cơ sở nhựa silicon và định hướng sử dụng (study on heat resistant paint material complex based on silicone and its applications) TT TIENG ANH

Therefore, thesis oriented to manufacture paints based on silicone resin using unmodified nanosilica, nano zirconium oxide and modified nano particles with PDMS to increase mechanical pr

AND TRAINING SCIENCE AND TECHNOLOGY

GRADUATE UNIVERSITY OF SCIENCE AND TECHNOLOGY

SUMMARY OF THESIS DOCTOR IN CHEMISTRY

Major: Organic Chemistry

Ha Noi - 2021

This thesis was complete at Graduate University of Science and Technology- Vietnam Academy of Science and Technology

Supervisor 1: Prof., Dr Nguyen Van Khoi

Supervisor 2: Dr Trinh Duc Cong

This thesis can be found at:

- Library of Graduate University of Science and Technology

- Vietnam National Library.

INTRODUCTION

1 Necessary of thesis topic

Heat-resistant paints are paints that can keep their technical properties at high temperature They can be used to protect many products and equipment working in extreme temperature conditions such as: aircraft, spacecraft, jet engines, boilers, furnaces and various vehicle components, The development and improvement in manufacturing of heat resistant paints are closely associated with development and creation of new heat resistant materials Heat resistant paints have been investigated with different types, both heat-resistant inorganic paints and heat-resistant organic paints such as Nippon, Jotun, Lemax, Hai Au, but there is no heat-resistant paint that simultaneously uses unmodified and modified nanosilica and nano zirconium oxide particles as heat-resistant fillers Therefore, author decided to choose heat-resistant paint based on silicone resin as research object of this thesis: “Study on heat resistant paint material complex based on silicone and its applications”

2 Objectives

Fabrication of heat-resistant paint based on silicone resin and some surface-modified and unmodified additives such as nanosilica, nano zirconium oxide,… so as to apply to coat on CT-18 engine tube

- Fabrication of heat resistant paint and study on some factors effect on coating’s properties

- Studying on influence of some technological factors on coating preparation on properties of paint film

- Studying influence of external environmental conditions on silicone paint film

- Constructing technical specifications of heat resistant paint based on silicone resin

- Orienting to use heat-resistant paint based on silicone to coat CT-18 engine tube and testing

CHAPTER 1 OVERVIEW 1.1 Heat restant paint introduction

1.2 Modification of nanosilica and nano zirconium oxide and their application in heat resistant paint

1.3 Application of heat resistant paint

On the basis of literature reviewed, there have been currently many studies on modifications of SiO2 surface such as by PDMS, PMHS, MSMA, polymer chain grafting, However, studies on ZrO2 surface modification is hardly mentioned Therefore, thesis oriented to manufacture paints based on silicone resin using unmodified nanosilica, nano zirconium oxide and modified nano particles with PDMS to increase mechanical properties and heat resistance of coating At the same time, study on coating technology and orientation of coating use on CT-18 engine tube

CHAPTER 2 EXPERIMENT 2.1 Materials, chemicals, tools and equipment

2.1.1 Materials

- Polymethyl phenyl siloxan: SILRES@ REN 50 Resin

- TiO2 (R996), TiO2 content ≥ 95%

- TiO2 (R5566), TiO2 content ≥ 93%

- Aluminium paste (GLS-65), solid content: 67%

- Aluminium paste (ZQ-40813), solid content: 62%

- Nano ZrO2, Nanoparticles Labs, ZrO2 content ≥99%

- Nano ZrO2 (XFI-013), ZrO2 content ≥99%

- Nano SiO2, Nanoparticles Labs, SiO2 content ≥95,9%

- Nano SiO2 (Fusil 300), SiO2 content ≥99,99%

- Polydimethyl siloxan (PDMS); dimethyl carbonat (DMC)

- Methanol, NaOH, HCl 36,5%, KOH, axetone, DOP, xylene, bentonite

2.1.2 Equipment

In addition to common tools and equipment used in laboratory, some other equipment was used in thesis research such as: Eurostar 20 high speed digital - IKA rod stirrer, Skymen JP ultrasonic vibration device -040, pearl mill ZM1.4DB3311, autoclave reactor with PPL core

2.2 Methods

- Paint manufacturing method;

- Sample preparation;

- Coating inside of CT-18 engine tube;

- Coating’s properties ditermination;

- Methods of testing environmental resistance of heat-resistant paint;

- Analytical methods determine properties of materials;

- Surface modification of nanosilica particles and nano zirconium oxide

particles with polydimethyl siloxane (PDMS);

- Methods of testing heat resistance of coatings

CHAPTER 3 RESULTS AND DISCUSSION 3.1 Investigation, selection of paint composition

3.1.1 Aluminium paste analysis

Two types of aluminum pastes GLS-45 and ZQ-40813 were analyzed by dynamic light scattering method (DLS) for determining their size distribution and alumium paste GLS-45 was selected for further studies

3.1.4 Nano zirconium oxide

Two types of nano zirconium oxide powders Nanoparticle Labs and

XFI-013 were analyzed by dynamic light scattering method (DLS) for determining their size distribution and nanosilica powder Nanoparticle Labs was selected for further studies

3.1.5 Silicone resin analysis

Table 3.5 Results of analysis of technical

parameters of poly methyl phenyl

siloxane

characteristics of silicone resins

(polymethyl phenyl siloxan - SILRES@ REN 50, Waker – Germany) was conducted Results were shown in table 3.5 and figure 3.21, results showed that solid content of this silicone resin is about 40%; specific weight 1.03 g/cm3; solvent is xylene Thermal analysis (TGA) was shown in figure 3.21, this indicated that silicone resin decomposes at temperature higher than 400 oC

Figure 3.21 TGA cure of silicone resin

3.2 Modification of nanosilica and

nano zirconium oxide with PDMS

3.2.1 Modification of nanosilica

3.2.1.1 Effect of the temperature on

surface modification of nanosilica

Thermal gravimetric analysis

(TGA) of modified nanosilica at

different temperatures were shown in

Figure 3.22, 200 oC was selected for

further studies

3.2.1.2 Effects of nanosilica and

PDMS mass ratios on surface

modification of nanosilica

The results of the analysis in

figure 3.23, theory of selecting the

optimal reaction conditions of surface

transformation between nanosilica

temperature of 200 oC with a

nanosilica/PDMS ratio of 1/0.75

3.2.1.3 Characteristic properties of

the surface modification of nanosilica

* Spectrum infrared sample nanosilica

before and after transformation

Figure 3.24 showed decification

process of attachment PDMS

monomers to surface of nanosilica

particles through a chemical reaction

with silanol group on surface of

nanosilica particles

* Structure of the surface modification

of nanosilica

SEM results showed that

nanosilica powders before and after

modification Modified nanosilica

powders has a larger particle size

* Chemical composition of modified

nanosilica surface

Figure 3.26 showed that after

modification carbon content increased

significantly to 24.61% This meant that

Figure.22 Effect of temperature on nanosilica surface modification productivity

Figure 3.23 Effect of nanosilica oxide/PDMS

on productivity of nanosilica oxide surface modification processsing

40 60 80

Figure 3.24 FT-IR of nanosilica

and modified nanosilica

nanosilica

Figure 3.25 SEM of nanosilica surface and modified nanosilica

organic groups had appeared on

nanosilica surface

* Evaluation of ability to

disperse pre- and post-volatile

nanosilica particles in organic

solvents (xylene)

a After 0 h b After 1 h c After 4 h d After 24 h e After 72 h

Figure 3.27 Dispersion ability of modified nanosilica and nanosilica in xylene

Figure 3.27 showed that modified nanosilica particles had better dispersion ability than the neat nanosilica particles

Thermal analysis (TGA) of

zirconium oxide nano samples at

different temperatures 200 oC was

nanoparticle surface modification

with PDMS

3.2.2.2 Effect of nano zirconium

oxide/ PDMS ratio on modification

processing

Figure 3.29, showed that, nano

zirconium oxide/PDMS ratio

reduced would lead to weight loss

increased and gained balance point

at about 750 oC, however, nano

zirconium oxide/PDMS reached

1/0.75 and 1/1 weight loss đi not

change much in comparison with

1/0.5 ratio So, nano zirconium

oxide/PDMS ratio at 1/0.5 was

chosen for modification of nano

Figure 3.28 Effect of temperature on

modification processing

Figure 3.29 Effect of nano zirconium

oxide/PDMS on productivity of nano zirconium oxide surface modification

processsing Figure 3.26 Energy-dispersive X-ray spectroscopy

of modified nanosilica oxide

Figure 3.32 Energy-dispersive X-ray spectroscopy of modified nano zirconium oxide

zirconium oxide with PDMS at

200oC

3.2.2.3 Characteristic features of

modified nano zirconium oxide

* FT-IR of nano zirconium oxide

before and after modification

Figure 3.30, showed that

modification processing had attached

monomers of PDMS onto surface of

nano zirconium oxide by chemical

reaction of Zr-OH on surface of nano

zirconium oxide

*SEM of modified nano

zirconium oxide

Figure 3.31 indicated chỉ

the same as nanosilica, modified

nano zirconium oxide particles

had bigger sizes than neat nano

zirconium oxide particles,

however, size increasing was not

so great And after denaturation

process, nanoparticles tended to

separate more than the

undenatured ones

* Chemical composition of

modified nano zirconium oxide

Figure 3.32, showed that

after modifying carbon content

increased strongly and reached

15.98 % This meant that organic

group had appeared on surface of nano zirconium oxide particles

* Evaluation of ability to disperse pre- and post-volatile nano zirconium particles in organic solvents (xylene)

a After 0 h b After 10 h c After 20 h d After 24 h e After 72 h

Figure 3.33 Dispersion ability of modified nano zirconium oxide and nano zirconium

oxide in xylene

zirconium oxide Figure 3.25 SEM of modified and unmodified nano

zirconium oxide

4000 3500 3000 2500 2000 1500 1000 500 40

50 60 70 80 90 100

Figure 3.30 FT-IR of nano zirconium oxide

before and after modification

Figure 3.3 showed

that modified nano

zirconium oxide particles

had better dispersion

ability than the neat nano

zirconium oxide particles

3.3 Fabrication of heat

resistant paint and study

on effect of some factors

on coating properties

3.3.1 Effect of Aluminium

paste and TiO 2 ratio on heat

resistance ability and some

properties of silicone coating

* Effect of Aluminium paste

and TiO2 ratio on heat resistance

ability of silicone coating

Table 3.9 indicated that, when

Aluminum paste decreased, coating

heat resistant ability increased, when

TiO2 content reached 15% and

aluminium paste decreased to 6%

coating heat resistant ability

decreased

silicone resin

Figure 3.34 showed that,

aluminium paste and TiO2 enhance

heat resistance ability of coating

properties of coating

From results of table 3.10,

aluminium paste/TiO2 ratio by wt

% of 12/9 was chosen

Table 3.8 Composition of silicone paint

No Components Weight percent (wt %)

M Al18Ti3 M Al15Ti6 M Al12Ti9 M Al9Ti12 M Al6Ti15

Table 3.9 Effect of Al paste/TiO2 ratio on

coating heat resistance ability

Table 3.10 Effect of Al paste/TiO2 ratio on

mechanical properties of coating

No Samples

Mechanical properties of coating Flexural

strength (mm)

Adhesion (points)

Relative hardness

on coating thermal properties

3.3.2 Effect of coating

thickness on coating heat

resistance ability

Table 3.12, showed that,

coating thickness increased

coating heat resistance ability

decreased, coating thickness of

about 200 µm was chosen

3.3.3 Effect of drying process

on coating properties

For thickness samples of

about 50 µm used drying process as MS-1; For thickness samples of about 200

µm and above used drying process as

MS-2

3.3.4 Effect of nanosilica content on heat resistance ability and mechanical properties of coating

* Effect of nanosilica content on heat resistance ability of silicone coating

Table 3.14 Effect of nanosilica content of coating heat resistance ability

* Note: KD: Unchanged, RN: Crack, BT: Blistering

Figure 3.36 Photos of dried smaples

Figure 3.35 Diagrams of drying process with

different thickness samples

Table 3.12 Effect of Al paste/TiO2 ratio on mechanical properties of coating

Table 3.14 and figure 3.37 showed that, nanosilica content reached 0.6% at about 700 oC, cracks appeared, temperature to 750 oC event nanosilica content of above 0.8 % could not improve coating heat resistance ability

Figure 3.37 Photos of coating samples with different nanosilica content

Results were shown in table 3.15, nanosilica content of about 0.6 in

MAl12Ti9 was chosen

Table 3.15 Effect of nanosilica content on some mechanical properties of coating

Table 3.17 Effect of nano zirconium oxide content

on heat resistance ability of silicone coating

Table 3.17 and figure 3.39 showed that, after testing in Nabertherm furnace at 1,300 oC for 20 - 25 seconds, nano zirconium oxide content increased heat resistance ability increased as well When nano zirconium oxide content reached 0.9%, at temperature up to 950 oC, coating was blistered, raised temperature to 900 oC even nano zirconium oxide increased, coating heat resistance ability was unchanged

Table 3.18 showed that nano zirconium oxide about 0.9 % is the best

3.3.6 Effect of mixture nanosilica and nano zirconium oxide content on heat resistance ability and mechanical properties of coating

* Effect of mixture nanosilica and nano zirconium oxide content on heat resistance ability of coating

Table 3.20 Effect of mixture nanosilica and nano zirconium oxide content

on heat resistance ability of coating

(Note: KD: Unchanged, PR: Blistering)

Doing experiments in 25 seconds at different temperatures Table 3.20 and figure 3.41 showed that, mixture nanosilica and nano zirconium oxide content increased heat resistance ability of coating increased as well However, content of mixture reached 1.2 % heat resistance ability of coating decreased and blistering points appeared at 1,050 oC

a MSi0.25Zr0.25 b MSi0.75Zr0.75 c MSi1.0Zr1.0 d MSi1.2Zr1.2

- TGA analysis

Figure 3.42 showed that, when adding more mixture nanosilica and nano zirconium oxide enhanced coating thermal stability

Figure 3.42 Effect of mixture nanosilica and nano zirconium oxide content

on coating thermal properties

* Effect of mixture nanosilica and nano zirconium oxide content on mechanical properties of silicone coating

Results were showed in table 3.21, ratio of mixture nanosilica/nano zirconium oxide as 0.75/0.75 was chosen

Table 3.21 Effect of mixture nanosilica and nano zirconium oxide content on

mechanical properties of silicone coating

3.3.7 Effect of mixture modified nanosilica and modified nano zirconium oxide content on heat resistance ability of coating

Table 3.23 showed that, modified nanosilica/ modified nano zirconium oxide ratio decreased coating heat resistance ability increased, however, coating heat resistance ability decreased when the ratio reached 0.25/1.25 Samples with nanosilica/ nano zirconium oxide of 0.75/0.75 and 0.45/1.05 coating can suffer from 1,050 oC in 25 seconds

Table 3.23 Effect of mixture modified nanosilica and modified nano zirconium

oxide content on heat resistance ability of coating

MSi0.75Zr0.75BT and MSi0.75Zr0.75 appeared small crack on surfaces, for

MSi0.45Zr1.05BT with ratio of 0.45% modified nanosilica and 1.05% modified nano zirconium oxide there was no change

- TGA analysis

Figure 3.44 showed that, modified nanosilica and modified nano zirconium oxide reduced thermal properties of coating, however, the reduction was not much, so modified nanosilica/ modified nano zirconium oxide as 0.45/1.05 (MSi0.45Zr1.05BT) was chosen