Performance Of Attapulgite And Its Application In Polyurethane Leather

Attapulgite is a kind of rare natural clay minerals with fibrous or acicularstructure. Owing to its properties,such as special crystal structure and superficialcharacter, attapulgite possesses fine adsorptive, rheologic, catalytic and fillingcapabilities, which endow it with ion exchange, heat stabilization, salt resistance,coagulation, pulping and phase change (in high temperature) performance.Accordingly, attapulgite has high application value.As the third big resources world wide of attapulgite minerals, our state found andbegan to explore attapulgite application in early 80's, and have made it goodapplication in many fields, such as absorption, decoloration, deodorization,salt-resistant slurry and so on. However, the in-depth processing and more abroad useof attapulgit capability remain in investigative stage, which is the importantinvestigative way presently. The degree of purity and granularity are the two kinds ofsignificant index for high subjoin-value production of attapulgite, which is the mainintention of in-depth processing too. However, the study reports about the two aspectsare few at the present time.In this thesis, it was chosen that the attapulgite form Xuyi (Jiangsu) as material,super milling and purification as the main investigative content, PU Leather as themain applied field. The structure and appearance change of attapulgite aftermechanical super milling, purification and its application in PU Leather wereinvestigated systemically. The main tasks are, (1) to explore the way of in-depthprocessing in order to get the base data and the reference, (2) to provide theorygroundwork for attapulgite application, (3) to develop applied field and economicvalue of attapulgite. There is certain praxis meaning in this thesis, due to its makingtheory study from applied angle.In the first chapter, the base character, the use (especial in macromoleculematerial), the mechanical super milling and purification actuality of attapulgite wereextensively discussed through referring large amount of literature and data. The studythought and blue print were drawn out in detail at this base.In the second chapter, planetary-style ball mill was chosen to give attapulgite - IV -super milling. Effect of milling time, dry ball milling and wet ball milling on crystalstructure and surface performance of attapulgite was studied systemically bygranularity, BET relative surface area, FT-TR spectroscopy, X-ray powder diffraction(XRD) and scan electron microscopy (SEM) analysis. The change of attapulgite aftermilling was investigated by rheology and static absorption analysis. Dependence ofsuper milling of attapulgite on milling aid and milling time were explored respectively,choosing six milling aid including both inorganic (sodium silicate) and organic(stearic acid) milling aid. The result show, in mechanical milling process, granularityof attapulgite is able to meet super milling qualification, after dry milling 1 h withoutmilling aid. There was no basic change for attapulgite granularity and moleculestructure when milling 2, 3 and 4 h, but out-of-order degree of crystal increasecorrespondingly. Quadric reunite take place after milling more than 5 h, whichresulted in increasing of granularity rapidly, damaging of fiber configuration badly,physical and chemical character changed accordingly. When dry milling, milling aidcan not only decrease granularity effectively but also protect fiber crystal structure.However, this process only round fiber crystal-bundle into sphere, not achievedisperse aim, which means dry milling unable to carry out disperse aim whether havemilling aid or not. Sodium hexametaphosphate, stearic acid and polyacrylic acid canassistant milling finely, which were all good milling aids. Wet ball milling can notonly protect crystal structure but also mill and disperse attapulgite into fiber crystal,meeting the requested standard. When choose water as milling medium, effect ofmilling with no milling aid is a...