Experiment § "Living polymerization" of free radicals
The methods of polymer polymerization can be divided into two categories: Stepwise reaction and Chain reaction. When we want to design a copolymer structure, gradual polymerization can put different monomers in different stages, and it is easier to complete the initially created form. In the chain polymerization system, the life of the reaction center of ionic polymerization (including cationic polymerization and anionic polymerization) is very long. Even if the reaction has ended, the reactive ions can remain in the system for a while. If another reactive monomer is inserted during this period, another different molecular structure can grow at the end of the original molecular chain, classified as a block copolymer.
In the system of chain polymerization, the polymerization reaction with free radicals cannot obtain the structure of the segmented copolymerization because the reactive free radicals have a short lifespan. When the reaction is terminated, the free radicals will also be destroyed. However, there is no way to introduce another monomer for the next stage of copolymerization (Figure 1).
In 1997, Ciba published the technology of nitroxyl adjustment polymerization, using the structure of R1-ONR2R3 as a free radical initiator (Figure 2). This structure will decompose into R1 and ONR2R3, two free radicals, R1, at high temperatures. This free radical can polymerize with monomer A. At the end of the reaction, the free radicals at the end of the polymer chain will react with the original nitroxyl radicals to form a new nitroxyl structure R1(A)x-ONR2R3. This new nitroxyl structure will still decompose two free radicals at high temperatures; one is R1(A)x. , the other is. ONR2R3. The former is reactive. At this time, if another monomer B is put in, the one-stage copolymerization structure of R1(A)x(B)y can be reflected (Figure 3).
Through nitroxyl groups, free radical polymerization will also have the characteristics of "living polymerization" like ionic polymerization. The chemistry is fantastic, right?
Note: The pictures provided in this article are modified from Ciba's technical data.
─Author: Dr. Ming-xu, Li, Everwide Chemical
Exhibition § The 36th Taipei International Electronics Industry Technology Exhibition
Co-sponsored by the Taiwan External Trade Development Council (TAITRA) and the Taiwan Electrical and Electronic Manufacturers' Association (TEEMA), The 36th Taipei International Electronics Industry Technology Exhibition, the 4th Taiwan International RFID Application Exhibition, and the 3rd Taiwan Broadband Communications Exhibition will be displayed at the Nangang Exhibition Hall of Taipei World Trade Center from October 11 to 14, 2010. Everwide Chemical released a new generation of plastic materials-related exhibits in Taipei International Electronics in 2009, which received widespread response and encouragement. This year's Taipei International Electronics Industry Technology Exhibition, the Everwide Chemical R&D team once again launched this year's latest technology products, such as moisture hardening glue, mobile phone key-related application products, IMD, lithographic ink, LED lights, solar energy industry-related materials, bicycle components Relevant application materials, thermal board, soft glue, and sheet glue are all the latest and greatest products in the industry. Everwide Chemical wholeheartedly welcomes your visit and advice!
Date: October 11 to October 14, 2010
Venue: World Trade Center Nangang Exhibition Hall; Booth No.: I0930, I0932, I1029, I1031.
Knowledge § What are the two major components of composite materials?
Composite materials are anisotropic materials that combine the advantages of two or more different substances to antagonize the compositional properties.
Composite materials usually include a Matrix and a Reinforcement. In most polymer-based composite materials, the former represents resin, and the latter represents fiber.
Living § What cabin do you take?
Because of frequent business trips to Shanghai, from the first Taoyuan-Hong Kong transfer, later Taichung-Jeju Island transfer, and finally Taoyuan-Shanghai direct flights; even Taichung-Shanghai also has direct flights. The flight journey did not reduce the ticket price due to the shortened time and fuel consumption, and it was probably more than 15,000 yuan. Every time I buy a ticket from a travel agency, I complain and tell them, "The price is about the same for the five days in Jiangnan. I don't have anything on my business trip, and it's still so expensive." The price of ten group tickets may be less than 10,000, and the airlines are in the same economic class, and they play the ticket period and cabin. The code behind the cabin class means different prices. It may be hot in peak seasons, and the cheap price seats will be removed or reduced, which will cause the latter to be expensive. And getting on the plane is the same treatment. Of course, the group ticket is the worst, putting the passenger on the bottom of the plane and getting on the plane first; when getting off the aircraft at the latest, coupled with the loud engine noise, it is always unsettling when flying on the plane. The same thing, different prices, is a fun place in the adult world. The more expensive the airline industry can sell, the better, and the airport can draw more taxes. "Time is money," so the direct flight fare should be a bit more expensive, so it's not wrong to say that. Even a carbon tax will be added in the future, and it is impossible to say that traveling on business is environmental protection. I don't know if you like it or not?
─Author: Mr. Hui-xu, Li, R&D Engineer, Everwide Chemical
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