The Structure And Properties Of A Novel Micro Conical Twin-screw Extruding Machine Used For Research

In this thesis,the structure and performance of a new kind of experimental miniature twin-screw extruder(QE31A)were investigated.Firstly,the stability of the QE31A extruder was studied and the suggestions of QE31A extruder structure improvement was put forward.Secondly,the self-cleaning property,circulation mixing property and reaction extrusion property of the QE31A extruder were further researched by experiments.This paper mainly from the following two parts:(1)The stability property of QE31A extruder:in this paper,poly caprolactone(PCLS),poly butyl diacid butyl glycol ester(PBS),linear low density polyethylene(LLDPE),polypropylene(PP)and polyurethane(TPU)of five kinds of common resins of the laboratory respectively mixed with three kinds of filling materials were used to do fatigue test experiment and used for testing the stability property of QE31A extruder.In the process of experiments,it was found that QE31A extruder has the following disadvantages:(1)more material residued inside the screw and cylinder lead to low extrusion production rate;(2)the self-cleaning property of QE31A extruder is not very good,which was difficult to clean the two screws after using the QE31A extruder.To solve above problems,this paper gives the specific solutions:Firstly,the screw thread and reflux tank of QE31A extruder was improvement partially,which the quality of the material added increased from 15.0 g to 20.0 g at a time and extrusion production rate increased from 36.5%to 55.0%on average;Secondly,according to the second question,effective wash was researched and the results showed that the cleaning effect of washing materials was the best when the quality ratio of LLDPE/CaC03 was 5:5.And the scientific principle of cleaning materials was explored and the interface problem between the polymer materials and steel was mentioned.The experimental results proved that interfacial adhesion between nonpolar polymer materials and steel was weak but the interface adhesion between polar polymer materials and steel was strong.(2)The circulation mixing property and the reaction extrusion property of QE31A extruder:PCLS,LLDPE and PP were respectively used to mixing experiment in QE31A extruder with starch,which the quality ratio of materials was 1:1.Under the same experimental conditions and different mixing time,which the purpose of the experiment was to preliminarily study the effect of mixing time on the circulation mixing property of QE31A extruder.In a similar manner,three kinds of composite materials of St70P20PUP10,SP45P45PUP10 and Ce45P45PUP10 were respectively used to do experiment in QE31A extruder through reactive extrusion.Under the same experimental conditions and different mixing time,which the purpose of the experiment was to preliminarily study the effect of mixing time on the reaction extrusion property of QE31A extruder.The experimental results showed that the mechanical properties of the same composite materials were stronger when the mixing time was 5.0 min.It was means that the circulation mixing and the reaction extrusion properties were better when the mixing time was 5.0 min.Under the same experimental conditions,the three kinds of composite materials as the same above were respectively prepared through the mixer.And the mechanical properties and micromorphology of the composites were tested and compared with those of the corresponding reactive extrusion materials.The experimental results showed that the material force value of the same composite material was lager than that of the reactive exteusion molding process.The main reason is related to the horizontal type of QE31A extruder,and thus in this paper,the suggestion of improvement of the horizontal to vertical type models was put forward.