Study On Expanding Sand Milling Preparation And Application Of Waterborne Micro-nano Thin Layer Graphite Materials

The coatings industry plays a very important role in the construction and development of the national economy.Since traditional coating products are mostly oily,which endanger the environment and people's health,do not meet the development requirements of green and environmental protection.There is an urgent need to develop environment friendly coatings.Nano-sized graphene is a new type of graphite material with many excellent properties and applying it to coatings can not only improve the coating properties,but also give the coatings new functions.However,the preparation cost of graphene is relatively high and its high hydrophobicity makes it difficult to apply to the preparation of waterborne coatings.Therefore,this thesis presented a new method for the expansion-dispersion-sand milling of micro-nano thin layer graphite materials,which suitable for the preparation of waterborne anticorrosive and waterproof coatings and low-cost.Applied it to waterborne acrylate anticorrosive coatings,waterborne alkyd resin anticorrosive coatings,waterborne acrylate waterproof coatings,and waterborne polymer cement waterproof coatings,tested the performance of each coating by reference to the standard,and the results were analyzed and discussed.(1)The graphite powder can be prepared by sanding and dispersing under the action of dispersant,coupling agent and the like after heating and expanding.The obtained waterborne micro-nano thin layer graphite material had a good dispersion effect,with a thickness of about 5 nm ~ 27 nm,a width of about 5 ?m ~ 50 ?m,an average particle diameter of about 17 ?m,and a median diameter D(50)of about 20 ?m.(2)The performance indexes of the waterborne micro-nano graphite acrylate anticorrosive coatings and waterborne micro-nano graphite alkyd resin anticorrosive coatings prepared by the waterborne micro-nano thin layer graphite materials can meet the standard requirements.Among them,the waterborne micro-nano graphite acrylate anticorrosive coatings had excellent water resistance.The sample plate was still intact after soaking in water for 720 hours,far exceeding the standard requirements of 48 hours,and had excellent waterproof effect.The performance of drying,water resistance and saltwater resistance of waterborne micro-nano graphite alkyd resin anticorrosive coatings were well,which had short drying time and fast speed,and the water and saltwater resistance time longer than alkyd resin anticorrosive coatings which doesn't contain waterborne micro-nano thin layer graphite materials.The volatile organic content(VOC)of the two anticorrosive coatings was less than 10 g/L and 37 g/L,which are far less than the requirement of 300 g/L,and was green and environmentally friendly.(3)Waterborne micro-nano thin layer graphite materials can enhance the drying,water resistance and saltwater resistance of waterborne acrylate waterproof coatings,among which water resistance was more prominent.Compared with the blank group,the waterproof coatings with the addition of 2% ~ 10% the waterborne micro-nano thin layer graphite materials can reach surface dryness within 3 hours and actual dryness within 5 hours.After soaking in water and saltwater for more than 96 hours,there was still no abnormal sample plate.And with the increase of the amount of waterborne micro-nano thin layer graphite materials,the longer the water and saltwater resistance time,the denser the coatings.The effect of waterborne micro-nano thin layer graphite materials on waterborne polymer cement waterproof coatings was slightly different from that of waterborne acrylate waterproof coatings.With the increase of the amount of waterborne micro-nano thin layer graphite materials,the impermeability of waterborne polymer cement waterproof coatings were increased.But when the amount of waterborne micro-nano thin layer graphite materials were increased,its tensile strength,elongation at break,water resistance,and saltwater resistance were hardly changed.This method successfully realizes the micro-nano waterborne preparation of graphite powder with simple process and low cost.Compared with the current price of graphene with a thickness of 10 nm up to 10,000 RMB per kilogram,the micro-nano graphite materials with a thickness of about 100 nm can be reduced to tens of RMB per kilogram.It is the ideal size for coatings and is low cost.Graphite materials are superhydrophobic and their sheet-like structure will significantly enhance the compactness of the coatings,thus the anticorrosive and waterproof performance of the coatings are significantly improved,and has wide application potential in the industry.