Surface Treatment Of Nano/micro Materials And Its Application In Polymer Base Composites

Dispersibility of nano/micro materials in polymer has an effect on the properties of composites directly. Their dispersibility is the key factor to materials' utility. Different nano/micro materials have different physical and chemical properties such as surface groups, electrification, and charge distribution. It is very difficult to eliminate these influence factors completely by conventional treatment. Surface properties and surface treatment of ultrafine red phosphorus and MMT and their interface properties with polymer matrices were studied in this thesis. The results were characterized by GC, FTIR, XRD, DTA, TG, XPS, UV, SEM, TEM and other physical and chemical methods. The main contents are as following:1. The study of factors influencing ultrafine red phosphorus's invariability and phosphine liberation indicated red phosphorus undergone oxidation and dismutation reaction in air, and trace ion of iron, copper and nickel fastened water absorption and oxidation, in which the effect of copper ion was the most, while aluminium and zinc ion could slow down red phosphorus' oxidation, and silver ion had the best effect on red phosphorus moisture absorption. Inhibitors such as aluminium hydroxide, magnesium hydroxide, organic phenol and ferrous potassuim cyanide had a good effect on reducing red phosphorus moisture absorption and restraining phosphine liberation.Microencapsulated ultrafine red phosphorus with aluminum hydroxide was prepared by sol-gel method, and the influence rule of reaction conditions on capsulation was studied. A part of impurity in ultrafine red phosphorus was removed by acid and water. Aluminium hydroxide macromolecule network gel was prepared by cheap industrial aluminium nitrate and acrylamide, and a uniform layer of encapsulation was formed on red phosphorus' surface by changing reaction conditions.Microencapsulated ultrafine red phosphorus was obtained after high temperature vacuum aging. The stability of micro-encapsulated red phosphorus was enhanced greatly.Selection of encapsulation materials and technics conditions were investigated when red phosphorus was encapsulated by organic materials. Melamine formaldehyderesin, coupling agents, and surfactants were used for encapsulating red phosphorus and stability and compatibility in organic system of micro-encapsulated red phosphorus were enhanced bonding The surface of red phosphorus was bonded with several macromolecule modifiers in batches according to polarity. Hence several well-knit layers of encapsulation was formed on red phosphorus' surface. The modified red phosphorus powder's surface and interface tension decreased to some extent, and the compatibility between inorganic and organic phase was improved , which would benefit red phosphorus' application in resin materials.The properties of flame retardancy, machanics, calorifics and pyrogenic decomposition dynamics were studied when PA66 engineering plastics with halogen free flame-retardants were modified by microencapsulated ultrafine red phosphorus cooperating with nano-magnesium hydroxide. When content of red phosphorus and magnesium hydroxide were 3% and above 5% respectively, the oxygen index was improved greatly. The sample could pass UL94V-0 vertical combustion test, and magnesium hydroxide reduced smoke when PA66 was burning; because of the effective surface treatment ,its good mechanics performance and fluidity were also maintained; pyrogenic decomposition activity energy of PA66/RP composites was measured by Flynn-Wall and Kissinger methods, which indicated that the reaction is first order reaction.2 Organic intercalating agent used for Na-montomorillonite (MMT), intercalation and intercalating mechanism were studied. The reaction conditions of cetyltrimethylammonium bromide(CTAB) modified MMT were investigated by viscosity experiment. The new cationic gemini surfactant (Gemini C12) had been synthesized and used for MMT's modification as organic intercalating agent. The result indicated that Gemini C12 had intercalated into the galleries of MMT and. increased...