马来酸酐与α-甲基苯乙烯共聚物的合成及其在PP/CaCO共混体系中得到应用的研究

摘要

Copolymerization refers to the chemical reactions or methods by which a copolymer can be synthesized. A copolymer is a polymer derived from two or more nonnumeric species. It is also known as a heteropolymer. Copolymers may be classified on the basis of how the monomeric units are arranged along the chain. They may also be classified in terms of the existence of, or arrangement of, branches in the polymer structure. In this thesis, the copolymerization of malefic anhydride and alpha-methyl styrene is presented. In this copolymerization process, isoamylacetate is used as a solvent and azobisisobutyronitrile (AIBN) is used as a free radical initiator. Maleic anhydride is an organic compound with the molecular formula, C4H2O3. It is a unique co monomer because it does not readily undergo homopolymerization, but forms copolymers without difficulty. It is also unique in that the copolymers that are formed in the presence of radical initiators are in a 1:1 ratio and in an alternating sequence. The copolymer composition is generally independent of the initial monomer ratio. Because of these characteristics, malefic anhydride has been used in the synthesis of many copolymers and terpolymers. Alpha-methyl styrene is a common comonomer and is usually used in the manufacture of plasticizers, resins and polymerization production processes. In the copolymerization reaction, the mixture of MAH,AMS and isoamylacetate solvent and AIBN was heated at varying temperatures. AIBN initiates the reaction by the formation of a free radical through the expulsion of nitrogen gas. One electron from the free radical combines with AMS and another electron from AMA combines with the MAH, thus breaking the double bond of MAH. The process is repeated to make a series of intermediate polymeric units. The copolymer formed was also subjected to a series of analyses. The GPC analysis results show that a greater yield of the product is achieved when both the temperature and the amount of AIBN initiator are increased. However, the results show that 70℃ seems to be the optimum temperature for this copolymerization reaction. The FT-IR analysis results were consistent with the polymer microspores of AMS/MAH copolymer. Major peaks shown were 2973 cm-1, 1858cm-1, 1779 cm-1, 1475-1600 cm-1 and 919 cm-1. Also, the 13C-NMR analysis results show that the copolymer has an alternating structure. The major peaks shown were between 136 and 140 ppm,30 and 68 ppm, 33-37 ppm, 37-42 ppm and 43-45 ppm. The SEM analysis shows that the uniform copolymer microspores were formed at various monomer concentrations, and the particle size increased continuosly with monomer concentration around 177 nm (0.5M) to 256 nm (1.0M), 464 nm (1.5M) and 750 nm (2.0M). The DSC analysis reveals that the temperature deviation started from 172-233℃, and the glass transition (Tg) was at 208℃, indicating that the product can be designed into many shapes and is stable up to 200℃. TGA analysis reveals weight losses at 75-140℃, then at 200℃, and then at 325-400℃ (at this temperature, 86.5％) of the material was decomposed. In combination with DTGA, the TGA results indicate that the copolymer is stable up to 340℃. The X-ray diffraction results show that the copolymer has a crystal structure (the appearance of peaks was at Theta values 11.9 and 18.5 degrees).The blending of the synthesized copolymer with polypropylene/calcium carbonate is also reported in this thesis. The dried polypropylene and maleic anhydride-alpha-methylstyrene copolymer pellets were mixed with CaCO3 at preselected mass ratios. This was necessary to improve the stiffness and impact toughness to the polypropylene. The effect of CaCO3 content on the essential work fracture (EWF) parameters and the influence of the maleic anhydridealpha-methylstyrene copolymer was studied. The extrusion of the mixtures described above was performed on a SHL-35 co-rotating twin-screw extruder with length to diameter ratio of 35; feed speed was 15 rpm, while the motor speed was 60 rpm. The temperature profile was in a range of 210-230℃. The materials were pelletized after extrusion and, after drying at 70℃ within 6-7 hours. The results from the tensile stress analysis show that elasticity and toughness have different behavior. When elasticity increases, toughness decreases, and when elasticity decreases, toughness increases. Also, when the weight of the copolymer increases, the tensile stress deceases. TEM analysis was done for the blending process. There were dark spots representing the calcium carbonate and white large particles representing the copolymer. The calcium carbonate is seen around the copolymer. This is because CaCO3 is an ionic compound (meaning, it has oppositely charged particles). The copolymer itself is a polar molecule due to the presence of the highly electronegative oxygen atoms. Therefore, the copolymer attracts the CaCO3. Similarly, SEM analysis was also done. The white particles indicate the CaCO3 filler. However, the structure showed CaCO3 filling the space in the polypropylene matrix. This probably has copolymer which seems indistinguishable from the CaCO3 filler. The X-ray diffraction results show that the pure polypropylene has a crystal structure. This is indicated by the appearance of peaks at Theta values less than 20 degrees (13.9, 15.9, 16.78, and 18.4 degrees). The scan was done from 5-90 degrees, but the results show that there was no change beyond 50 degrees. For the copolymer with PP/CaCO3 blend, the X-ray diffraction results also show that the shape resulting from the blending has a crystal structure. This is indicated by the appearance of peaks at Theta values less than 20 degrees. The peaks that appeared at Theta values greater than 50 degrees indicate CaCO3 and the scan was done from 5-90 degrees. The results show the appearance of peaks up to 82 degrees.

目录

英文文摘

论文说明：LIST OF FIGURES AND ILLUSTRATIONS、LIST OF TABLES、ABBREVIATIONS AND SYMBOLS

声明

CHAPTER 1 Introduction

1.1 Definition and overview of copolymers and copolymerization

1.2 Types of copolymers

1.3 Historical development of polymers and copolymers

1.4 An overview of maleic anhydride, alpha-methyl styrene, azobisisobutyronitrile (AIBN) and polypropylene

1.4.1 Maleic anhydride

1.4.2 Alpha-Methylstyrene

1.4.3 Azobisisobutyronitrile (AIBN)

1.4.4 Polypropylene (PP)

1.5 Research Objectives

CHAPTER 2 Review of some previously synthesized copolymers involving maleic anhydride and alpha-methylstyrene, as well as blending with polypropylene

2.1 Copolymers using maleic anhydride (MA)

2.2 Copolymers using alpha-methyl styrene (AMS)

2.3 Blending of copolymer

CHAPTER 3 Results and Discussions

3.1 Synthesis of the copolymer

3.2 Results from the analysis of the copolymer

3.2.1 IR Analysis

3.2.2 13C NMR Analysis

3.2.3 SEM Analysis

3.2.4 Differential Scanning Calorimetry (DSC)

3.2.5 Thermogravimetric Analysis (TGA)

3.2.6 X-ray Diffraction (XRD)

3.3 Results from the blending and injection of the copolymer

3.4 Results from the analysis of the copolymer after blending and injection

3.4.1 Scanning Electron Microscopy (SEM)

3.4.2 Transmission Electron Microscopy (TEM)

3.4.3 X-ray Diffraction

3.4.4 IR Analysis

CHAPTER 4 CONCLUSION

CHAPTER 5 EXPERIMENTAL SECTION

5.1 Synthesis of copolymer

5.1.1 Materials and equipment

5.1.2 Procedure

5.2 Molding and injection of copolymer with polypropylene/calcium carbonate filler

5.2.1 Materials and Equipment

5.2.2 Procedure

REFERENCES

ACKNOWLEDGEMENTS

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