Surveying some factors affecting the physical and chemical properties of polymer nanocomposite materials on the basis of polyamide 6, polycarbonate and multi - Wall carbon nanotubes

MINISTRY OF EDUCATION AND TRAINING VIETNAM ACADEMY OF SCIENCE AND TECHNOLOGY GRADUATE UNIVERSITY OF SCIENCE AND TECHNOLOGY ----------------------------- Ha Van Thuc SURVEYING SOME FACTORS AFFECTING THE PHYSICAL AND CHEMICAL PROPERTIES OF POLYMER NANOCOMPOSITE MATERIALS ON THE BASIS OF POLYAMIDE 6, POLYCARBONATE AND MULTI-WALL CARBON NANOTUBES Major: Theory Chemistry and Physical Chemistry Code: 9 44 01 19 THESIS OF CHEMISTRY DOCTOR Ha noi – 2019 The thesis is completed at: Institute for Tropical Technology, Vietnam Academy of Science and Technology –«— Science instructors: 1. Associate Professor. Dr. Tran Thi Thanh Van 2. Dr. Le Van Thu LIST OF ARTICLES OF AUTHOR 1. Ha Van Thuc, Tran Thi Thanh Van, Ngo Cao Long, Le Van Thu, Study on preparation of PA6/PC/SEBS/SEBS-g-MA/CNT materials by melt mixing method, Part 1: Manufacturing masterbatch, Vietnam Journal of Chemistry, Vol 56, 07-2018, 145-149. 2. Ha Van Thuc, Tran Thi Thanh Van, Ngo Cao Long, Le Van Thu, Study on preparation of PA6/PC/SEBS/SEBS-g-MA/CNT materials by melt mixing method, Part 2: Optimization of processing parameter, Vietnam Journal of Chemistry, Vol 56, 07-2018, 150-154. 3. Huynh Anh Hoang, Le Van Thu, Ha Van Thuc, Modification and investigation of properties of carbon nanotubes prepared from Vietnamese liquefied petroleum gas, Vietnam Journal of Chemistry, Vol 52 (6), 12-2014, 717-722. 4. Ha Van Thuc, Tran Thi Thanh Van, Ngo Cao Long, Le Van Thu, Investigation of the effect of carbon nanotubes on the properties of blend materials PA6/PC/SEBS/SEBS-g-MA, Journal of Chemistry, Physics and Biology, Vol 23, 3/2018, 89-93. 5. Ha Van Thuc, Tran Thi Thanh Van, Ngo Cao Long, Le Van Thu, Improve the compatibility of polyamide 6 and polycarbonate on the basis of using SEBS and SEBS-g-MA compatibilizers, Journal of Chemistry, Physics and Biology, Accepting. 1 A. INTRODUCTION TO THE THESIS 1. The urgency and purpose of the thesis research - The urgency of the thesis: Today, developing polymer nanocomposite materials on the basis of thermoplastic, thermosetting reinforced with nanomaterials to create good impact-resistant products is always studied. In fact, thermoplastics polyamides 6 (PA6), polycarbonates (PC) have been used as materials to produce many shockproof devices, especially in the field of national security, such as caps, armor, and body cladding. The equipment for that soldier requires good impact resistance, durability and lightness. PA6 has some preeminent properties such as durability with hydrocarbon solvents, wear resistance, good fatigue, toughness, high thermal stability, easy processing. The PC has the outstanding feature of high optical transparency, better impact resistance than most other thermoplastics. Among high-performance nanomaterials for thermoplastic resins, carbon nanotubes (CNT) are a typical agent. CNT has a very high and light mechanical strength. Therefore, if PA6, PC, and CNT are incorporated into a nanocomposite polymer, it is possible to create a potential material to produce impact-resistant equipment for the armed forces. - Purpose: Successful fabrication of polymer nanocomposite on the basis of PA6, PC thermoplastics, and CNT reinforcement to effectively apply the material system to the production of body protection equipment for the army forces. 2. Research content of the thesis (1) Fabrication of PA6/PC blend on the basis of using two compatible substances, SEBS and SEBS-g-MA. (2) CNT denaturation then fabricated polymer nanocomposite based on CNT modified with PA6/PC/SEBS/SEBS-g-MA. (3) Optimize machining parameters and determine suitable mixing sequences for polymer nanocomposite manufacturing. 2 (4) Testing production of some impact-resistant products (hand covers, helmets) from fabricated polymer nanocomposite materials. 3. Scientific and practical significance, new contributions of the thesis - Evaluation of dispersion level, interoperability between components and mechanical properties of polymer blends PA6/PC/SEBS/SEBS-g-MA and polymer nanocomposites PA6/PC/SEBS/SEBS-g-MA/CNT. - Construct the mixing process and the appropriate technological parameters for polymer nanocomposite manufacturing. - Experimental producting some anti-shock products used in the field of national security to meet the specific product standards of police and military. 4. The layout of the thesis The thesis has 138 pages including 6 sections: Opening 2 pages; Chapter 1 - Overview 38 pages; Chapter 2 - Experiment and research methods 14 pages; Chapter 3-Results and discussion 61 pages; List of works of the author 1 page; References 11 pages; Appendix 10 pages.. B. THESIS CONTENT CHAPTER 1: OVERVIEW The author has gathered 103 references on the content and research objects of the thesis including: Characteristics and applications of PA6, PC and some other thermoplastic. Overview of the situation of research, manufacture and application of polymer blends of thermoplastic resins with compatible substances, as well as polymer nanocomposites with thermoplastic matrix, especially PA6, PC with reinforcement CNT. Since then, the following conclusions are drawn: - PA6, PC is commonly used to make blend polymer and polymer nanocomposite such as PA6/PP, PA6/PE, PA6/PC, PA6/CNT, PC/CNT. Types of composites and blends have mostly improved impact resistance, elongation, breaking strength, etc. CNT has the ability to effectively enhance physical and mechanical properties for many polymer 3 nanocomposites. However, the positive effect of CNT is only clearly promoted when it is denatured to reduce the phenomenon of shrinkage, increase dispersion capacity and connect with the plastic matrix. - Many block polymers, graft polymers are used to make interactions between polymers in polymer blend, polymer nanocomposite. Typically, graft copolymers like PE-g-MA, PP-g-MA, EPR-g-MA, SEBS-g-MA, CHAPTER 2. EXPERIMENT AND RESEARCH METHOD 2.1. Materials PA6: MFI 10g/10min (230 0C, 2,16 kg), 1,36 g/cm3. PC: MFI 10,5g/10min (3000C, 1,2 kg), 1,2 g/cm3. SEBS: Kraton 1652, 0,91g/cm3, 20000u. SEBS-g-MA: SEBS2% anhydride maleic, Kraton 1901, 29% Styrene. MWCNT: CVD, d = 10÷ 80 nm, l = 10÷50µm, cleanness > 95%. 2.2. Devices Ultrasonic vibrating tank SW60H Elma 38 kHz. Brabender 2-screw mixer. SM210 injection molding machine, SHR super mixer, Coperion Keya molten mixer, injection molding machine M-70A-DM for mechanical samples. FT-IR Infrared Spectrophotometer IMPACT-410. D8 Advance Bruker X-ray diffraction spectrometer. DSC, TGA Labsys Stearam. SEM Hitachi S4800. TEM JEM-1010. Tinius Olsen H100KT versatile bending compressors and impact resistance Radmana ITR 2000. 2.3. Experimental methods 2.3.1. Prepare polymer blend PA6/PC/SEBS/SEBS-g-MA Samples PA6, PC, PA6 / PC, PA6 / PC / SEBS-g-MA, PA6 / PC / SEBS / SEBS-g-MA are prepared with varying components. The samples were mixed at the normal temperature and then added simultaneously to the 2-screw melt mixing chamber. 2.3.2. Prepare polymer nanocomposites PA6/PC/SEBS/SEBS-g-MA/CNT 4 2.3.2.1. CNT modification: CNT and HNO3 (63%) is mixed, ultrasonic vibrating, heating and stirring. The mixture is diluted with deionized water and filtered. Dry the sample in a vacuum oven. 2.3.2.2. Prepare polymer nanocomposites : Polymer nanocomposites is made through 2 stages: Drying and dehumidifying moisture, melt mixing. 2.3.3. Determination of polymer nanocomposites processing parameters Materials including PA6, PC, SEBS/SEBS-g-MA and CNT (modified) are mixed in proportion to 80/20/10/10 / 1,5 (pkl). Optimal sample machining parameters are determined including temperature, time and screw speed. 2.3.4. Prepare masterbatch of polymer nanocomposite 2.3.4.1. Process 1: PA6/PC/SEBS/SEBS-g-MA/CNT with the ratio of 80/20/10/10/1,5 (pkl) corresponding is mixed simultaneously to make polymer nanocomposite. 2.3.4.2. Process 2: In stage 1 only PA6/SEBS/SEBS-g-MA/CNT are mixed. At stage 2 PC is added. 2.3.4.3. Process 3: In stage 1, only PC/SEBS/SEBS-g-MA/CNT are mixed. In stage 2 PA6 is added. 2.3.5. Test production 2.3.5.1. Using numerical simulation method: The impact resistance of polymer nanocomposite materials is evaluated by Autodyn Ansys 12 simulation software. 2.3.5.2. Production of hand-covers and helmets: Hand covers and helmet after determining thickness and mold, they are test manufactured. 2.4. Methods of surveying the structure and properties of samples and testing product Survey of sample microstructures: FT-IR, XRD, EDX, viscosity flow of polymers, TGA and DSC. SEM, TEM morphology survey. Determination of mechanical properties: tensile strength, elongation, Charpy impact resistance according to ISO 179-1: 2010. 5 CHAPTER 3. RESULTS AND DISCUSSION 3.1. Survey of structure and properties of polymer blends PA6/PC/SEBS/SEBS-g-MA 3.1.1. Survey the physical properties of blend PA6/PC 3.1.2. Survey mechanical properties of blend PA6/PC/SEBS/SEBS-g-MA 3.1.2.1. Survey the influence of SEBS-g-MA on the mechanical properties of PA6 and PC The amount of SEBS-g-MA at about 10 (pkl) in blend PA6/PC can be a suitable level to facilitate the connection of PA6-PC phase, thereby increasing the mechanical properties of blend compared to original polymers. 3.1.2.2. Survey mechanical properties of blend PA6/PC/SEBS-g-MA Figure 3.3: Change of impact strength of blends PA6/PC/SEBS-g-MA with corresponding ratio x / 100-x / y with y = 0 ÷ 20 (pkl) The impact strength and elongation of the blend are much lower than the original polymers due to the incompatibility of PA6 and PC. Figure 3.1. The change of impact strength of blend PA6/PC according to the ratio of the plastic Figure 3.2: Change of impact strength of PA6/SEBS-g-MA and PC/SEBS-g-MA blends when SEBS-g-MA loading changes 6 3.1.2.3. Survey mechanical properties of blend PA6/PC/SEBS/SEBS-g-MA 3.1.3. Survey microstructure of blends PA6/PC/SEBS/SEBS-g-MA Figure 3.5: Fractured SEM image of blend samples: (a) PA6 / PC 80/20, (b) PA6 / PC / SEBS-g-MA 80/20/20 and (c) PA6 / PC / SEBS / SEBS-g-MA 80/20/10/10 (pkl) 3.1.4. Surveying the torque of blends PA6/PC/SEBS/SEBS-g-MA Figure 3.4: The change of mechanical properties of blend PA6/PC/SEBS/SEBS- g-MA in proportion to SEBS / SEBS-g-MA (a) (b) (c) Figure 3.6: Torque of blends: sample 1: PA6/PC 80/20; sample 2: PA6/PC/SEBS-g- MA 80/20/20 and sample 3: PA6/PC/SEBS/SEBS-g- MA 80/20/10/10 7 3.1.5. Infrared spectrum analysis of samples Figure 3.7: FTIR spectra of blends (a) PA6/PC/SEBS-g-MA; (b) PA6/PC The increase in intensity of peaks may be due to chemical interactions occurring between PA6 and SEBS-g- MA. The end amine groups (–NH2) of PA6 interacted with the maleic anhydride fraction (–MA) in the compatibilizer to form imit groups. 3.1.6. Interactive mechanism and dispersion pattern of the components in blend PA6/PC/SEBS/SEBS-g-MA Figure 3.8: The pattern of components distribution in blend, compatibilizers SEBS/SEBS-g-MA play a role as a bridge connecting PA6 matrix to PC Figure 3.9: Interactive mechanism to form a bridge between PA6 matrix and PC of SEBS/SEBS-g-MA in blend PA6/PC/SEBS/SEBS-g-MA 8 3.2. Survey of structure and properties of polymer nanocomposite based on blend PA6/PC/SEBS/SEBS-g-MA and CNT reinforcement 3.2.1. Structure and properties of CNT before and after modification 3.2.1.1. Survey of microstructure of CNT through SEM images Figure 3.10: SEM images of CNT: (a) before and (b) after modification (a) (b) Figure 3.11: SEM image describes the distribution state of CNT after modification Figure 3.12: SEM image determines the size of fiber CNT after modification (a) (b) Figure 3.13: TEM image of CNT: (a) before and (b) after modification 9 3.2.1.2. Infrared spectrum and X-ray dispersion spectrum of CNT Figure 3.14: FTIR spectra of CNT before (a) and after (b) modification CNT nature d (A0) CNT modified d (A0) Elements 3,423 3,409 C 2,096 2,104 Fe3C 2,021 2,024 Fe3C.n-Fe/C Figure 3.15: X-ray diagram of CNT before (a) and after (b) modification CNT nature CNT modified (a) (a) (b) (b) 10 Elements Weight (%) Atomic (%) Elements Weight (%) Atomic (%) C 92,35 98,42 C 85,85 90,53 Fe 0,44 0,10 Fe 0,35 0,08 O 10,91 8,64 Figure 3.16: EDX results of CNT before and after modification 3.2.1.3. Thermal properties of CNT before and after modification Figure 3.17: Results of thermal analysis in the air environment of CNT before (a) and after modification (b) 3.2.2. Structure and properties of polymer nanocomposite PA6/PC/SEBS/SEBS-g-MA/CNT 3.2.2.1. Effect of CNT on the mechanical properties of polymer nanocomposite PA6/PC/SEBS/SEBS-g-MA/CNT (a) (b) Figure 3.18: Change of mechanical properties of polymer nanocomposite when changing CNT loading 11 3.2.2.2. Survey thermal properties of samples 3.2.2.3. Investigating the morphology of samples Nnb (a) (b) PA6/PC 80/20 PA6/PC/SEBS/SEBS-g-MA 80/20/10/10 PA6/PC/SEBS/SEBS-g- MA/CNT 80/20/10/10/1,5 Figure 3.19: Thermal analysis diagram of PA6/PC/SEBS/ SEBS-g-MA and PA6/PC/SEBS/ SEBS-g- MA/CNT Figure 3.20: Surface SEM images of polymer nanocomposites PA6/PC/SEBS/SEBS-g-MA/CNT have the proportions of 80/20/10/10 /x respectively with x (a) 0, respectively (b) 1,5 and (c) 2,0 (pkl) (c) 12 3.3. Optimizing parameters in preparing polymer nanocomposite PA6/PC/SEBS/SEBS-g-MA/CNT 3.3.1. Effect of melt mixing temperature on structure and mechanical properties of polymer nanocomposite 3.3.1.1. Mechanical properties of polymer nanocomposite 3.3.1.2. Structural morphology of polymer nanocomposite 3.3.2. Effect of mixing time to the structure and mechanical properties of polymer nanocomposite 3.3.2.1. Mechanical properties of polymer nanocomposite (b) (a) Figure 3.21: Effect of melting temperature on the mechanical properties of polymer nanocomposite Figure 3.22: SEM image of polymer nanocomposites manufactured at mixing temperature: (a) 250 oC and (b) 260 oC Figure 3.23: Effect of mixing time on the mechanical properties of polymer nanocomposite 13 3.3.2.2. Structural morphology of polymer nanocomposite 3.3.3. Effect of screw speed on structure and mechanical properties of polymer nanocomposite 3.3.3.1. Mechanical properties of polymer nanocomposite 3.3.3.2Structural morphology of polymer nanocomposite 3.4. Manufacturing masterbatch of polymer nanocomposite PA6/PC/SEBS/SEBS-g-MA/CNT No. Location Temperature (oC) Table 3.1: Temperature of chambers in the injection molding machine to prepare polymer nanocomposites 1 Nozzle 260 2 T1 260 3 T2 257 4 T3 253 5 T4 250 (a) (b) (a) (b) Figure 3.24: Surface SEM images of polymers nanocomposite with mixing time: (a) 10 and (b) 15 (mins) Figure 3.25: Effect of screw speed on mechanical properties of polymer nanocomposites PA6/PC/SEBS/SEBS-g-MA/CNT Figure 3.26: SEM images of polymer nanocomposite were prepared with mixing speed: (a) 50 rpm and (b) 70 rpm 14 Figure 3.27: Materials mixing procedures for manufacturing polymer nanocomposite 3.4.1. Survey mechanical properties of polymer nanocomposite prepared by different procedures 3.4.2. Morphological survey of polymer nanocomposite is made according to different procedures Figure 3.29: SEM images of polymer nanocomposites are manufactured by different masterbatch creation procedures (1) (3) (2) Figure 3.28: Mechanical properties of polymer nanocomposites PA6/PC/SEBS/SEBS-g- MA/CNT prepared different procedures Procedure 1 Procedure 2 Procedure 3 15 3.4.3. Survey the time of mixing PA6 into masterbatch 3.5. Application of polymer nanocomposite PA6 / PC / SEBS / SEBS-g- MA / CNT to produce some anti-impact products 3.5.1. The results use numerical simulation methods to determine the optimal thickness for products 3.5.1.1. Results of numerical simulation for helmets a) Results of building geometric models and model meshing: Figure 3.31: Geometry model of helmet 0,01 mm 0,02 mm 0,04 mm (a) (b) (c) Figure 3.30: Influence of mixing time PA6 into masterbatch PC/CNT on mechanical properties of polymer nanocomposites Figure 3.32: Results of helmet model meshing by the following methods: (a) Tetrahedrons, (b) Dominant quad / tri, (c) Dominant All quad 16 b) Select material parameters and impact simulation calculation results 1 State equation Shock Table 3.2: Polymer nanocomposite standard model 2 Durable model von Mises 3 Destruction model Hydro (Pmin) Table 3.3: Parameters of state equation Equation of State Shock Reference density 1.14000E+00 (g/cm3 ) Gruneisen coefficient 8.70000E-01 (none ) Parameter C1 2.29000E+03 (m/s ) Parameter S1 1.63000E+00 (none ) Strength von Mises Shear Modulus 3.68000E+06 (kPa ) Yield Stress 5.00000E+04 (kPa ) Failure Hydro (Pmin) Hydro Tensile Limit -1.00000E+06 (kPa ) Reheal Yes Erosion None Maximum Expansion 1.00000E-01 (none ) Minimum Density Factor (SPH) 2.00000E-01 (none ) Figure 3.33: Characteristics of helmet structure changes during impact 17 Figure 3.34: Results of simulated collision calculation of helmet: (a) impact stress at collision speed of 10 m/s, (b) impact stress at collision speed of 20 m/s, (c) helmet deformation c) The survey results of the effect of materials producing helmets Figure 3.35: Change in impact energy during the collision of helmets made from different materials (a) (b) (c) PA6 PA6/SEBS-g-MA PA6/PC/SEBS/SEBS-g-MA 18 d) Results of surveying the thickness of helmets Figure 3.36: Deformation of helmets with different thickness 3.5.1.2. Results of numerical simulation for hand covers a) Results of building geometric models and model meshing HexDominant quad/tri, 0,01 mm Hex Dominant quad/tri, 0,05 mm (a) (b) 19 Tetrahedrons, 0,01 mm Hex Dominant quad/tri, 0,02 mm Figure 3.37: Geometric model and method of dividing suitable mesh of covering: (a) shoulder covers, (b) hand covers, (c) elbow covers, (d) arm covers b) Select material parameters and impact simulation calculation results Figure 3.38: Result of calculating stress and deformation in collision of the hand covers: (a) collision speed is 10 m/s, (b) collision speed is 20 m/s (c) (d) (a) (b) 20 d) The survey results of the thickness of the hand covers Figure 3.39: Deformation of hand covers with different thickness 3.5.2. Test producing hand covers and helmet using polymer nanocomposite PA6/PC/SEBS/SEBS-g-MA/CNT Table 3.4: Temperature in heating chambers in polymer nanocomposite extruder Chamber Nozzle T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 Temp (oC) 260 260 258 258 256 256 254 254 252 252 250 Table 3.5: Temperature in the compartments of the SM210 injection molding machine to produc test goods from nanocomposite materials Nozzle T1 T2 T3 T4 T5 260oC 258oC 256oC 254oC 252oC 250oC 21 Figure 3.40: Helmet and hand covers test products 3.5.3. Actual testing of quality helmet and hand covers products 3.5.3.1. Testing mechanical properties Figure 3.41: Mechanical properties of test products and laboratory polymer nanocomposite materials 3.5.3.2. Testing against beating sticks 22 Table 3.6: Anti-impact results of test products Products Results Helmet Hand covers Cracking phenomenon No cracks and no scratches No cracking Product structure Good elasticity, no distortion, the inner helmet system does not change. Good elasticity, no distortion 3.5.3.3. Test of anti-guillotine knives Table 3.7: Results of the anti-guillotine test of the test product Products Results Helmet Hand covers Cracking phenomenon No cracks and no scratches No cracking Product structure Good elasticity, no distortion Good elasticity, no distortion Depth of slash 1,25 mm 1,05 mm 3.5.3.4. Compare specifications between test products and standard products Table 3.8: Mechanical properties of test products compared to standards Objects Test products Standards Helmet Tensile strength: 111 MPa Impact strength: 787 J/m Weight ≤ 0,5 kg Tensile strength ≥ 40 MP a Impact strength ≥ 400 J / m Weight ≤ 0,65 kg 23 Against the beating sticks and knives of cutting according to the standards of the Ministry of Public Security Against the beating sticks and knives of cutting according to the standards of the Ministry of Public Security Hand covers Tensile strength: 111 MPa Impact strength: 787 J/m Weight ≤ 0.75 kg Against the beating sticks and knives of cutting according to the standards of the Ministry of Public Security Tensile strength ≥ 38 MP a Impact resistance ≥ 500 J/m Weight ≤ 0,85 kg Against the beating sticks and knives of cutting according to the standards of the Ministry of Public Security GENERAL CONCLUSIONS 1) Polymer blend PA6/PC/SEBS/SEBS-g-MA with the corresponding ratios of 80/20/10/10 (pkl) have achieved many mechanical properties superior to polymer blend PA6/PC. The impact strength of PA6/PC polymer blends with and without compatibilizers were 670,5 J/m and 50,2 J/m respectively. 2) Polymers nanocomposite PA6/PC/SEBS/SEBS-g-MA/CNT have the rate of 80/20/10/10/1,5 (pkl) with many changes in mechanical properties compared to polymer blend PA6/PC/SEBS/SEBS-g-MA has the same ratio. Impact strength and tensile strength of polymers nanocomposite with 1,5 (pkl) CNT corresponding to 730,5 J/m and 92 MPa. CNT reinforcement tends to disperse into PA6. The appearance of CNT in thermoplastic also significantly increases thermal stability compared to the original thermoplastic resins, as well as polymer blends with similar components. 3) Polymer nanocomposite PA6/PC/SEBS/SEBS-g-MA/CNT is processed with optimal parameters: melting temperature of 260 oC, mixing speed of 24 70 rpm and mixing time of 15 minutes. The manufactured polymer nanocomposite achieves the best mechanical properties, impact strength and tensile strength corresponding to 777 J/m and 98 MPa. 4) The most suitable mixing sequence for preparing polymer nanocomposite is to use the masterbatch PC/SEBS/SEBS-g-MA/CNT melted mixing with PA6. The proportion of components is 20/10/10/1,5 and 80 PA6 respectively (pkl). Masterbatch is melted for 6 minutes, the polymer nanocomposite is melted for 9 minutes. 5) Calculating numerical simulation with geometric model, elemental meshing method and physicochemical parameters of polymer nanocomposite by Autodyn Ansys 12 software has determined the optimal structure of the test production products (helmet and hand covers). Actual test results show a high suitability for the mechanical properties of the test products compared to the polymer nanocomposite manufactured in the laboratory. The test products meet the technical requirements in accordance with the helmet and hand covers sets of the Ministry of Public Security.