Influence of thermal aging on dispersion stability and mechanical stability of styrenebutadiene latex (SBL) was studied in various aspects as follows: 1. It was observed that with increasing the aging temperature, the SBL particles areeasy to coagulate together and to form a solid gel within a shorter time. However, thegelation ratio determined by Maron test is reduced during the thermal aging, indicatingthe increase in the mechanical stability for the thermal aged samples. To elucidate themechanism of the abnormal phenomenon, pH value, F"IIR, GPC, as well as stress-strainbehavior of the thermal aged SBL system were investigated. It was found that thereduction of dispersion stability is mainly due to lowering the barrier energy betweenthe latex particles, and thermal degradation of poly (styrene-butadiene) in the colloidstate is not oxidized into carbonyl group at the double-bond site, but turns intocross-linking between the macromolecules, resulting in a higher mechanical strength ofthe SBL film. Correlation of the tensile modulus to the gelation ratio demonstrated thatthe improvement of the mechanical stability is originated from crosslink-induced hightensile modulus of the SBL particles. 2. The reduction of dispersion stability during thermal aging was studied. Toelucidate the mechanism of this phenomenon, pH value, particle size, FTIR and ζpotential of an aged SBL system were investigated. It was found that a main reason ofthis reduction was caused by a decrease of pH value during thermal aging. Furtherexperimental results showed that a part of nonionic surfactant that is one of thecomposition elements of SBL system was decomposed into carboaylic acid, leading tothe decrease of pH value and thus a poor dispersion stability of SBL system. 3. Latex containers with different oxygen permeability were inversitgated for furtherclarifying the oxidation mechanism of SBL during the thermal aging. It was found thatthe bottles made from the different materials could change the thermal stability of SBLin different ways. The pH value changes in a completely different style compared withthat of gelation ratio determined by Maron test. Particularly, SBL in a bottle with lowoxygen permeability showed little change in stability after a long-term thermal aging,while the speed of pH value change is faster than the speed of gelation rate changedetermined by Maron test. The difference in this reaction behavior was explained fromthe difference of each oxidization degradation reaction. That is, oxygen has largeinfluence on the thermal aging of SBL. 4. Quantitatively prediction of SBL stability was established. In order to establishthe hi沙-precision prediction method, temperature measurement of many places in theworld was carried out and the input quantity of heat in practical enviorment wasclarified, and the activation energy of the chemical reaction about mechanical stabilityand dispersing stability following aging was calculated. The predicted result withArrhenius model was compared with the result of actual storage samples, and it wasconfirmed that they have accorded extremely. 5. To improve of the strength of latex film, grafted carbon nano-particle was added into the latex system. It was found that the increase of GCB increases the film strength.SEM and TEM observations showed that GCB is distributed SBR more uniformaly thanthat of carbon black without grafting. It is very interesting that grafted molecularcould be dissociated from the surface of carbon, and replaced by SBR molecules. Thisshould be the mechanism of reinforcement of GCB/SBR system.Keywords: Styrene butadiene latex; Dispersion stability; Mechanical stability; Thermalaging, Polymer degradation. Influence of thermal aging on dispersion stability and mechanical stability of styrenebutadiene latex (SBL) was studied in various aspects as follows: 1. It was observed that with increasing the aging temperature, the SBL particles areeasy to coagulate together and to form a solid gel within a shorter time. However, thegelation ratio determined by Maron test is reduced during the thermal aging, indicatingthe increase in the mechanical stability for the thermal aged samples. To elucidate themechanism of the abnormal phenomenon, pH value, F"IIR, GPC, as well as stress-strainbehavior of the thermal aged SBL system were investigated. It was found that thereduction of dispersion stability is mainly due to lowering the barrier energy betweenthe latex particles, and thermal degradation of poly (styrene-butadiene) in the colloidstate is not oxidized into carbonyl group at the double-bond site, but turns intocross-linking between the macromolecules, resulting in a higher mechanical strength ofthe SBL film. Correlation of the tensile modulus to the gelation ratio demonstrated thatthe improvement of the mechanical stability is originated from crosslink-induced hightensile modulus of the SBL particles. 2. The reduction of dispersion stability during thermal aging was studied. Toelucidate the mechanism of this phenomenon, pH value, particle size, FTIR and ζpotential of an aged SBL system were investigated. It was found that a main reason ofthis reduction was caused by a decrease of pH value during thermal aging. Furtherexperimental results showed that a part of nonionic surfactant that is one of thecomposition elements of SBL system was decomposed into carboaylic acid, leading tothe decrease of pH value and thus a poor dispersion stability of SBL system. 3. Latex containers with different oxygen permeability were inversitgated for furtherclarifying the oxidation mechanism of SBL during the thermal aging. It was found thatthe bottles made from the different materials could change the thermal stability of SBLin different ways. The pH value changes in a completely different style compared withthat of gelation ratio determined by Maron test. Particularly, SBL in a bottle with lowoxygen permeability showed little change in stability after a long-term thermal aging,while the speed of pH value change is faster than the speed of gelation rate changedetermined by Maron test. The difference in this reaction behavior was explained fromthe difference of each oxidization degradation reaction. That is, oxygen has largeinfluence on the thermal aging of SBL. 4. Quantitatively prediction of SBL stability was established. In order to establishthe hi沙-precision prediction method, temperature measurement of many places in theworld was carried out and the input quantity of heat in practical enviorment wasclarified, and the activation energy of the chemical reaction about mechanical stabilityand dispersing stability following aging was calculated. The predicted result withArrhenius model was compared with the result of actual storage samples, and it wasconfirmed that they have accorded extremely. 5. To improve of the strength of latex film, grafted carbon nano-particle was added into the latex system. It was found that the increase of GCB increases the film strength.SEM and TEM observations showed that GCB is distributed SBR more uniformaly thanthat of carbon black without grafting. It is very interesting that grafted molecularcould be dissociated from the surface of carbon, and replaced by SBR molecules. Thisshould be the mechanism of reinforcement of GCB/SBR system.Keywords: Styrene butadiene latex; Dispersion stability; Mechanical stability; Thermalaging, Polymer degradation.