HGMS/TPU Composite Foam Fabrication and Property Analysis

摘要

In the past couple of years, a lot of research work has been published on polymeric foams.Thisis probably due to the role they play in their application in many fields or their low weight whichleads to light, impact absorbing structures where applied.However, these foams do not meet therequirements for high performance applications like withstanding high compressive strength atlow density.Many researchers have concentrated on the development of foams by synthesisusing new polymers and a number of papers have been published on reinforced thermoplasticpolyurethane (TPU) foams using the mentioned approach.
　　 This study examined recent developments in hollow glass microspheres (HGMS) reinforcedpolymeric foams with particular reference to polyurethane composites.Thermoplasticpolyurethane foams were successfully prepared from commercial grade TPU polymer usingextrusion and compression molding.Hollow glass microspheres were selected as the reinforcingmaterials.To enhance interfacial adhesion between filler and the matrix, three methods ofsurface modification were studied.FT-IR and SEM were used to analyze and observe themodified surfaces and morphology of fabricated foam.Density, hardness and mechanicalproperties of the foam were also tested.
　　 FT-IR and SEM analysis showed that, using NaOH to hydroxylate the surface of HGMS led to auniformly modified surface structure of the HGMS which was desirable for reinforcing TPUfoam, although HCL gave good surface structure as per FT-IR, SEM observations showed lackof uniformity in the surface structure of the HGMS.Increasing the content of foaming agentfrom 1％ to 2％ decreased the tensile strength of the foam by about 50％.The tensile strengthdecreased by about 40％ when the content of HGMS was increased from 0％ to 3％.Thecompressive strength of the composite foam increased by 47％ when the content of HGMS wasincreased from 0％ to 7％.Increasing HGMS content led to a decrease in the density and increasein hardness of the foam with lowest densities realized with compression molding.After a 75％compressive force, SEM observation of 7％ HGMS reinforced TPU foam showed a more stablestructure than 5％ HGMS reinforced foam.

目录

声明

Dedication

Acknowledgements

Abstract

Abbreviations

List of figures

List of tables

1 Literature review

1．1 Introduction

1．1．1 Thermoplastic polyurethanes(TPU)

1．1．2 Hollow glass microspheres(HGMS)

1．2 HGMS/TPU composites

1．3 Particle/matrix interface adhesion

1．4 Performance of composite foam

1．5 Fabrication method

1．6 Density and void content of syntactic foams

1．7 Strength and failure mechanisms

1．8 Impact resistance of foams

1．9 Head impact model

1．10 Leg impact model

2 Materials and experiments

2．1 Surface modification

2．2 Materials

2．3 Fourier transform infra-red spectroscopy

2．4 Scanning electron microscope

2．5 Molecular weight

2．6 Thermal analysis

2．7 High speed mixing

2．8 Rheological studies

2．9 Extrusion molding

2．10 Injection molding

2．11 Compression molding

3 Results and discussions

3．1 Modification analysis

3．2 TPU molecular weight

3．3 Morphology and dispersion analysis

3．3．1 HGMS surface morphology

3．3．2 Morphology of extrusion foam

3．3．3 Morphology of compression molded foam

3．3．4 HGMS dispersion

3．4 Thermal analysis

3．5 Rheology

3．6 Mechanical analysis

3．6．1 Tensile strength

3．6．2 Compression test

3．6．3 Hardness test

3．7 Density

4 Conclusion and recommendation

5 References