| The formation mechanism of slurry erosion is very complex. Traditionally, the investigation on slurry erosion mainly focuses on the erosion behavior of metal or ceramics. The structure of polymer is greatly different from the one of metal or ceramics and more complicate than the latter, so the primary erosion theory doesn't explain or simulate the polymer erosion phenomena. The most emphases of the previous work have been put on the effect of erosion condition on erosion resistance of specimen, but the investigation on the effect of the polymer or polymer composite material themselves on erosion resistance is relatively little. The composite material was prepared with the different resin as the matrix and brown fused alumina as the reinforcement material. They will develop along the two directions—high impact resistance and high heat resistance on the precondition of enough erosion resistance.Phenoxy resin/alundum composite material was prepared through the crossblend and hot pressing. The effect of alundum content, grainsize, size distribution on erosion wear rate, impact resistance and heat deformation temperature (HDT) was studied. The results show that the erosion wear rate is 1.407×10-4cm/h in alundum content of 83.3% and grain size of mesh 80. It is superior to 45# steel and close to 316L stainless steel. The impact strength is 6.89KJ/m2 and HDT is common. The theoretical calculation and bulk density experiment testified that the alundum can fill the phenoxy resin more effectively when the particle diameter ratio is more than 5:1 and the mass ratio of big and small is about 7:3. The practical experiment result shows that the minimum erosion wear rate after gradation is 0.911×10-4cm/h at practical diameter ratio of 80#:360# and mass ratio of big and small of 80:20.The toluene diisocynate and isocyanate-terminated polyurethane prepolymer with different molecule weight were added to phenoxy resin to form crosslink structure. Molecule weight and addition level of crosslinking agent have obvious effect on tensile property. Based on this, phenoxy resin/PU/alundum composite material was prepared. The effect of alundum content, grain size, size distribution on the erosion wear rate and impact resistance was investigated. The results show that the most tensile strength of modified phenoxy resin increases at first and than decreases with the augment of prepolymer molecule weight and addition level. Breaking extension enhances continuously at the same time. The theoretical derivation of elastomer erosion has proved that strong and ductile material has better erosion resistance. The phenoxy resin/PU/alundum composite material was prepared in the PU prepolymer molecule weight of 2300 and isocyanate index of 0.16. The minimum erosion wear rate after gradation is 0.441×10-4cm/h and the erosion resistance is four times that of one of 45# steel. Even when filler level of alundum is very high (85.3%), the impact resistance of phenoxy resin/PU/alundum composite material reaches 23.72 KJ/m2.The properties of epoxy composite material with different epoxy curing system as matrix were researched and the epoxy E-44/phenol resin system was chosen by reason of its better combined properties. Considering its weak ductility, E-44/phenol resin/alundum composite material was prepared with phenoxy resin as toughener. The results show that the phenoxy resin and epoxy E-44/phenol resin can form semi-IPN structure (semi-interpenertrating networks structure) in phenoxy resin content of 15%. Here, the erosion wear rate abates 36.9% than the one of non-phenoxy resin and impact resistance enhances 10.75%. The minimum erosion wear rate after gradation is 1.74210-4cm/h and impact resistance is 3.64KJ/m2. The modification effect of silicane coupler KH-560 is superior to the one of KH-550. The erosion wear rate decreases 17.4% and impact strength enhance 45.9% and HDT increases 8℃in KH-550 content of 1%.With the blending of phenoxy resin and phenol resin as the matrix resin, the studies was carried out on the effect of technological conditions on the properties of phenoxy resin/phenolic resin/alundum composite material, such as phenolic resin category, phenoxy resin/phenolic resin rate, alundum gradation, silane coupler type and addition level. The results show that thermoplastic phenolic resin, especially, the high ortho position novolac phenolic resin offers the composite material excellent HDT but the erosion wear rate is higher than the one of resole phenolic resin. The combined properties of composite material is the best in phenoxy resin/phenolic resin of 1:1, alundum gradation of 80#:360#, 80# content of 80%. Here, the erosion wear rate is 0.831×10-4cm/h; impact strength is 1.77 KJ/m2 and HDT is 138.1℃. The effect of the KH-550 is limited. The KH-560 has the active epoxy functional group so the reinforced effect is obvious. In the KH-550 content of 1%, the erosion wear rate debases 14.3% and the impact resistance improves 53%; the HDT enhances 6.7℃.New fashioned FB boron-containing phenolic resin replaced general phenolic resin in order to improve the heat resistance of the epoxy resin/phenol resin curing system in essence. Boron-containing phenol resin/E-44/alundum composite material was prepared in reference to the fourth part. The effect of different FB resin/E-44 ratio, curing time and curing temperature, filler gradation and silane coupler on properties of FB resin/E-44/alundum system was investigated. The results show that little FB resin can greatly increase the heat resistance of epoxy resin. In FB resin/E-44 proportion of 2:8 (mass ratio), the curing produce 5% thermal decomposition temperature exceeds 360℃after stage cure. The percentage of retention exceeds 50% above 600℃owing to the low decomposition rate. Based on this FB/E-44 rate, the FB resin/E-44/alundum composite material has outstanding erosion resistance, which lowest erosion wear rate is equivalent to one of 316L stainless steel. They have the impact resistance in the range of 2.92～2.61 KJ/m2 and HDT in the range of 79.1～81.7℃. The modification effect of KH-550 is better than the one of KH-560. The erosion wear rate reduces 18.87%; impact strength enhances 26%; HDT aggrandizes 4.4℃in the KH-550 addition level of 1% alundum mass.
|
PDF Full Text Request