Method for promoting iP-1-B to form I' crystals directly from melt through monomer copolymerization
A ip-1-b, copolymerization technology, applied in the field of a small amount of monomer copolymerization to promote iP-1-B to form I' crystal directly from the melt, can solve the problem of changing crystal form, low tensile modulus and strength, comprehensive mechanics Performance impact and other issues, to achieve the effect of less comonomer
Active Publication Date: 2018-07-10
TIANJIN UNIV
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Problems solved by technology
However, it should be noted that when the comonomer content is relatively high, the comonomer can introduce more structural defects in the iP-1-B molecular chain, which can directly form a thermodynamically stable I' crystal from the melt, and also It will change the crystalline form and reduce the crystallinity, thermal stability and melting point, etc., and will be affected to a certain extent in terms of comprehensive mechanical properties, especially the tensile modulus and strength will be lower
Therefore, as far as the prior art is concerned, the homopolymer iP-1-B is not easy to directly form a thermodynamically stable crystal structure from the melt, while the copolymer containing a high content of comonomer can directly form part or all of the thermodynamically stable crystal structure from the melt. Stable crystalline structure, but its comprehensive mechanical properties are restricted, and often can be obtained directly from the melt such as I' crystal at a lower melting temperature
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[0026] The technical solutions of the present invention will be further described below in conjunction with specific embodiments.
[0027] Weigh 7g of iP-1-B98# (Shandong Dongfang Hongye Chemical Co., Ltd., copolymerized iP-1-B, with an identical mass fraction of 98%, and a melt flow rate (MFR) of 1.31g / 10min (190°C / 2.16kg), propylene feed percentage 3-5%), preheated with a flat vulcanizer at 180°C for 10 minutes, then gradually increased the pressure to 25MPa by gradually increasing pressure, kept at the highest pressure for 3 minutes, and then cold pressed at 25MPa 8 minutes, pressed into a 0.5mm thick sheet sample, took it out and left it at room temperature for 30 days (24×30 hours), so that the formed II crystal was basically transformed into I crystal, as shown in the attached figure 1 shown.
[0028] Cut the sample into 1mm 2 Large and small square flakes, wrapped in aluminum foil, controlled by linkam hot stage, using a heating rate of 5°C / min, observing the melting...
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The invention discloses a method for promoting iP-1-B to form I' crystals directly from melt through monomer copolymerization. Propylene and 1-butylene copolymer is subjected to heating heat preservation and cooling, meanwhile, the melt crystallization behavior of the copolymer is observed in situ through wide-angle X-ray scattering, it is found that only II crystals formed by the copolymer and homopolymerized iP-1-B are different, a small number of I' crystals can be generated while the II crystals are mainly formed, then in the multi-time cyclic heating and cooling process that the temperature is raised to 125 DEG C and then reduced to 30 DEG C, more crystal forms I' can be generated by the propylene monomer copolymerized iP-1-B obviously compared with the homopolymerized iP-1-B, along with increase of 30-125 DEG C cyclic heating and cooling frequency, the proportion of the generated I' crystals is increased, and the method is simple in process and easy to operate.
Description
technical field [0001] The invention belongs to the technical field of polymer processing, and more specifically relates to a method for promoting iP-1-B to form I' crystal directly from a melt through copolymerization of a small amount of monomers. Background technique [0002] Isotactic poly-1-butene (iP-1-B) is a thermoplastic resin belonging to the semi-crystalline polyolefins known for its good mechanical properties, outstanding creep resistance, low temperature flow resistance and environmental stress cracking resistance Durability, wear resistance, flexibility and high filler filling, etc., known as "plastic gold", currently mainly used in hot water pipes, synthetic fibers, food packaging, medical equipment and other fields. As a polycrystalline polymer, iP-1-B crystallizes under different conditions to form five different crystal forms I, II, III, I', and II', of which the crystal form II is a thermodynamically metastable tetragonal crystal, and the molecular chain ...
Claims
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Login to View More IPC IPC(8): C08F210/08C08F210/06B29C43/02
CPCB29C43/02C08F210/08C08F210/06
Inventor 李景庆蔡晓倩蒋世春尚英瑞
Owner TIANJIN UNIV