The influence of silicon rubber self-adhesive tape blending carbon black varieties and ambient temperature on volume resistivity
Block both ends of the molecule (CH3)3aOV2 (CH=CH)(CH3) SiO chain link with a mole fraction of 0.15%, a degree of polymerization of about 6,000 methyl vinyl silicone rubber raw rubber 100 parts, hydrochloric acid absorption The amount is 0.2 mL/g. The iodine adsorption value is 48 mg/g, the specific surface area is 32 m2/g, and 30 parts of carbon black a are mixed in a kneader to form a rubber compound. The rubber material is mixed with 1 part of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane on a two-roll rubber mixer to form a conductive mixed silicone rubber. For comparison, replace carbon black a with the same amount of hydrochloric acid. The absorption capacity is 3.2 mL/g, the iodine adsorption value is 58 mg/g, and the specific surface area is 58 m2/g carbon black b. The same method is used for mixing Silicone Rubber. Two kinds of mixed silicone rubbers were vulcanized by hot pressing at 170 °C for 10 min to prepare test pieces with a thickness of 1 mm, and then vulcanized in a 200 t oven for 4 h. Then, measure the volume resistivity of two conductive silicone rubbers at various temperatures,
Influence of Carbon Black Variety and Environmental Temperature on Volume Resistivity
In order to obtain a conductive mixed silicone rubber with good abrasion resistance and conductivity, a primary particle size of 60~120 ran and a DBP oil absorption of 0.70~1. 2 mL/g of reinforced conductive carbon black should be selected. This furnace carbon black can be uniformly dispersed in the silicone rubber, and while imparting good conductivity, it also acts as a reinforcing agent. The commonly used acetylene conductive carbon black contains graphite crystals in its structure due to the manufacturing method, and has poor affinity with the raw rubber rubber, which not only has poor reinforcement, but also deteriorates physical properties. On the contrary, the furnace carbon black prepared by burning creosote in a high temperature furnace does not contain graphite crystals, which can improve the physical properties and wear resistance of silicone rubber. Carbon black used in rubber is usually selected from the perspective of reinforcing effect, that is, from the perspective of wear resistance, the primary particle size is 40 rnn or less, preferably 20 rnn or less, and from the consideration of imparting conductivity, it is also hoped that the primary particle size is below 40 rnn. Within the above range. Compared with the molecular chains of other organic rubbers, the molecular chain of raw silicone rubber has very good flexibility. Choosing carbon black with a moderate primary particle size, that is, carbon black with a primary particle size of 60-120 mn, can improve the reinforcement. The DBP oil absorption of 0.70 to 1.2 mL/g is an indicator of the usual furnace carbon black, and when the primary particle size is 60 to 120 nm at the same time, it means that its specific surface area is small. The specific surface area is related to the surface adsorption force. Carbon black with a small specific surface area has a small surface adsorption force. It is easy to disperse when used in cassia rubber raw rubber and can achieve good conductivity. This kind of reinforcing conductive carbon black can be combined with other types of conductive carbon black and other additives such as flame retardants and heat resistance additives in appropriate proportions.
