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Method for accelerating crystallization of isotactic poly 1-butylene by shear flow

A technology of shear flow and butene, applied in the field of polymer crystallization kinetics, can solve problems affecting industrial applications, slow crystal growth rate, and small number of nuclei

Inactive Publication Date: 2015-05-13
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Isopoly-1-butene can exist in various crystal forms, crystallized from the melt under normal pressure to generate a square Π-type crystal form formed by stacking 11 / 3 helical chains, without adding nucleating agent or without When an external field is applied, the number of nucleation is small and the crystal growth rate is slow, which affects its industrial application. Therefore, it is of great significance to study the crystallization kinetics of isotactic poly-1-butene

Method used

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  • Method for accelerating crystallization of isotactic poly 1-butylene by shear flow
  • Method for accelerating crystallization of isotactic poly 1-butylene by shear flow
  • Method for accelerating crystallization of isotactic poly 1-butylene by shear flow

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] 1. Raise the temperature of the flat vulcanizer to 170°C, keep the pressure at 20bar for 5 minutes, and press the poly-1-butene particles into a sample of a certain thickness;

[0025] 2. Place the laminated poly-1-butene sheet in the shear cell, and heat it to the heat treatment temperature of 200°C at a rate of 30°C / min;

[0026] 3. Adjust the height of the shear cell so that the sample reaches a predetermined thickness of 10um; at the same time, keep the sample at the heat treatment temperature for 5 minutes to eliminate its thermal history;

[0027] 4. Lower the temperature to the crystallization temperature of 85°C at a rate of 30°C / min;

[0028] 5. Keep at the crystallization temperature for a sufficient time to completely crystallize the sample.

[0029] as attached figure 1 As shown, under the condition of static isothermal crystallization, only spherulites are formed, and the number of spherulites is small and the size is large.

Embodiment 2

[0031] 1. Put the laminar poly-1-butene laminated film with a flat vulcanization mechanism in Example 1 in the shearing cell, and heat it to a heat treatment temperature of 200° C. at a rate of 30° C. / min;

[0032] 2. Adjust the gap value of the shear cell so that the sample reaches a predetermined thickness of 10um; at the same time, keep the sample at the heat treatment temperature for 5 minutes to eliminate its thermal history;

[0033] 3. Lower the temperature to the crystallization temperature of 85°C at a rate of 30°C / min;

[0034] 4. Immediately after the temperature drops to the crystallization temperature, a shear flow field is applied to the sample, the shear rate is 10s-1, and the shear time is 5s;

[0035] 5. Keep at the crystallization temperature for a sufficient time to completely crystallize the sample.

[0036] as attached figure 2 As shown, when the shear rate is 10-1s, the number of spherulites increases, and the time for the crystals to cover the field o...

Embodiment 3

[0038] 1. Put the laminar poly-1-butene laminated film with a flat vulcanization mechanism in Example 1 in the shearing cell, and heat it to a heat treatment temperature of 200° C. at a rate of 30° C. / min;

[0039] 2. Adjust the gap value of the shear cell so that the sample reaches a predetermined thickness of 10um; at the same time, keep the sample at the heat treatment temperature for 5 minutes to eliminate its thermal history;

[0040] 3. Lower the temperature to the crystallization temperature of 85°C at a rate of 30°C / min;

[0041] 4. Immediately after the temperature drops to the crystallization temperature, a shear flow field is applied to the sample, the shear rate is 20s-1, and the shear time is 5s;

[0042] 5. Keep at the crystallization temperature for a sufficient time to completely crystallize the sample.

[0043] as attached image 3 As shown, when the shear rate is 20-1s, the system first forms columnar crystals and then spherulites. Compared with Example 1 ...

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Abstract

The invention discloses a method for accelerating crystallization of isotactic poly 1-butylene by shear flow, when the temperature is reduced from heat treatment temperature to the crystallization temperature, the isotactic poly 1-butylene is applied with shear flow, and is fully crystallized by maintaining for enough time. The heat treatment temperature is 200 DEG C, and thermal history can be eliminated by maintaining for 5min at the heat treatment temperature. The isothermal crystallization temperature is 85 DEG C, the shear rate is 10-40s<-1>, and the shear time is 5S. According to the method, macromolecular chains in mesomorphic phase are in directional arrangement along flow direction, the entropy of crystallization can be reduced, the number of crystal nucleus is increased significantly, and the crystal growth period is decreased to accelerate the crystallization of 1-butylene.

Description

technical field [0001] The invention belongs to the field of polymer crystallization kinetics, and more specifically relates to a method for accelerating polymer crystallization kinetics by applying shear action to polymer supercooled melt. Background technique [0002] The structural formula of poly-1-butene is --(H2C-CH(C2H5))n--, Tg=-25°C, Tm=96-136°C, it belongs to semi-crystalline polymer. Thermal creep, good resistance to stress cracking, resistance to wet abrasion, chemical reagents, tasteless, non-toxic, odorless, especially can be used for a long time at a temperature of 90-100 ° C, so it can be used as a hot water pipe; its performance Similar to PVC soft material, it can be blended with other polyolefin polymers to expand its application range. Poly-1-butene (i-PB) with high isotacticity and high crystallinity is called "plastic gold" and is one of the most advanced chemical materials in the world. [0003] Isopoly-1-butene can exist in various crystal forms, cr...

Claims

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Application Information

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IPC IPC(8): C08J3/00C08L23/20B29B13/00
Inventor 关培培李景庆尚英瑞蒋世春
Owner TIANJIN UNIV
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