Orientation And Crystallinity Of Bi-Component Fibres Determined By Wide Angle X-Ray Diffraction (WAXD)

The project was realized in EMPA(Swiss Federal Material Research and Testing Laboratory) and the experiment part was performed in the crystallography laboratory of ETH Zurich(Swiss Federal Institute of Technology) for 6 months.The project is one part of "PHA tendon" Project whose aim is to design an article tendon with high biodegradable and mechanical properties.The article tendon can work as a temporary supporter during the recovery period of a real tendon.For analysing the biodegradable and mechanical properties,it needs to analyser the orientation and crystallinity of fibres.Hence,the aim of the project is to propose a new method of WXD(Wide Angle X-Ray diffraction) measurement and evaluation for bi-component fibres and to apply it to two kinds of bi-component fibres.The traditional methods are only suitable for the single crystal grain.The new method enlarges the application of this equipment and also applies a new data source for measuring the properties of bi-component fibres.For realising the aim,a suitable sample holder for fibres was designed due to the traditional one can only be used for single crystal grain firstly.This part was finished in the prepare step of this project. Then,the project will focus on defining a series of experimental parameters:the distance between the samples and the detector,x-ray irritation time and the choice of holder type.After the definition, choose the suitable parameters and the best calibrate for bi-component fibres.The step can make the results of measurement more precise. Here,an x-ray irritation to the sample holder is necessary and regard the diffraction pattern obtained as the background.An adjustment of the background can avoid the misunderstanding from the air in the measure environment to the measurement's results.In the quantitative analysis part,the traditional methods are required to be modified because they are base on the single crystal sample.New methods have some additional steps for dealing with the data to adapt the complicated orientation and crystallinity properties of bi-component fibres.When calculating the orientation,the additional step can separate the diffraction intensities of two diffraction arcs.For calculating the crystallinity,the additional step can resolve the diffraction pattern of each component and make the treated data suitable for the classical formula.Finally,the new method of measurement and analysis were applied to two kinds of bi-component fibres which are totally different, poly(3-hydroxybutyrate-co-3-hydroxyvalerate)(PHBV)-Polylactic acid(PLA) and Polyphenylene Sulfide(PPS)-Polyester(PET) bicomponent fibres,to verify its justifiability.The data from the measurement can apply data for the discussion about the relationship between the spinning parameters(draw ratio,the figure of core/sheet and content ratio) and the properties of orientation and crystalline. From the results,if the draw ratio is higher,the orientation is higher. But the figure of core/sheet and content ratio do not affect the orientation and crystallinity evidently.