| Including adding Intensifiers such as fibre glasses and taking use of orientedcrystallization, many experiments have been done to study the reinforcement ofplastic pipe before. Bur many studies can't reinforce the pipes on axial and circularproperties at the same time. So we take use of one shearing-drawingtwo-dimensional stress field pipe-extrusion die to study the problem. By simplemethods of pipe molding and under industrial productivity, polyolefin pipes whoseaxial and circular properties reinforced by SGF or themselves, simultaneously hadbeen manufactured successfully. The mechanical properties,crystalline morphologyand crystal structure,oriented crystallization theory,shearing-inducingcrystallization theory,molecular microstructure and reinforcing mechanism of pipe,practicability and economic results of polyolefin pipe extruded by the twoequipments in this study had been analysed and discussed in this thesis synthetically.It was found that:1,Under industrial productivity, axial and circular strength of these pipes hadbeen improved by the equipments. The results as follows: (1),The highest circularstrength of PP F401 pipes had been increased more than 21％to36.07MPa. Its axialhighest strength had been increased 21.1％to 38.25MPa. (2),The highest circularstrength of PP B8101 pipes had been increased more than17％to25.54MPa. Its axial highest strength had been increased 14.8％to27.73MPa. (3),Both of the axial andcircular properties of shearing-inducing crystallization pipes of PP B8101:PP F401had been improved obviously, especially the properties of PP B8101 (8％): PP F401(92％) pipes achieved the best effects. Its axial highest strength had been increased14.3％to 41.2MPa. Its circular highest strength had been increased 14.3％to41.5MPa.Also the properties of PP BS101 (3％): PP F401 (97％) pipes achieved thenice effects, whose axial highest strength had been increased 10.7％to 39.67MPa.and circular highest strength had been increased 20.6％to 42.99MPa. (4),The axialhighest strength of HDPE 1158(5％):PE2480(95) pipes had been increased 13.7％to24.42MPa. Its circular highest strength had been increased 21.9％to 25.38MPa. (5),The axial highest strength of PP F401 pipes reinforced by 30％S G F R P P hadbeen increased more than 10.5％to 38.68MPa. Its circular highest strength had beenincreased 22.0％to 42.1MPa.2,The degree of axial and circular orientations of reinforced pipes were betterthan that of the conventional pipes. The lamellar thickness and its homogeneity,crystallinity,heat resistance of reinforced pipes were better than those of theconventional pipes too.3,Molecular microstmcture of reinforced pipes were composed of muchmicrofibril which was arranged regularly and oriented finely. There were muchtie-molecular between the crystals and they had becometwice-oriented-crystallization interlocking shish-kebab structure obviously. So theaxial and circular properties of pipes had been improved.4,Theβ-crystals had been achieved in both reinforced pipes of PPB8101(40％):F401 (60％) and PP B8101,F401.In the reinforced pipes of SGF/PP,SGF oriented on two-dimensional but also the polymer molecular chains had beenoriented and crystallized twice. They improved the two-dimensional properties ofpipes together.5,Phenomena of shearing-inducing crystallization appeared in reinforced pipesobviously. And the effects were more obvious when a little of HDPE 1158 whosemolecular weight is high had been added to HDPE 5421B whose molecular weight is low relatively. So interlocking shish-kebab structure of twice-oriented-crystallizationhad been achieved, which improved the axial and circular properties of polyolefinpipes simultaneously. Also When little B8101 is added to F401 the shearing-inducingcrystallization is well improved.
|
PDF Full Text Request