TW201321424A - Biomass-derived shape-memory polyurethane material and manufacturing method thereof - Google Patents

Abstract

Provided is biomass-derived shape-memory polyurethane materials and a manufacturing method thereof. The manufacturing method includes steps of: (a) preparing PLA: preparing one or more biomass-derived PLAs; (b) preparing pre-polymer: reacting PLA of step (a) with isocyanate in a NCO/OH molar ratio of 1.0 to 1.4 to form the pre-polymer terminated by the isocyanate; and (c) preparing biomass-derived shape-memory polyurethane material: reacting the pre-polymer of step (b) with one or more chain extension agents to form the biomass-derived shape-memory polyurethane material. The biomass-derived shape-memory polyurethane material made from the method of the present invention has potential of application on the field of medical equipments.

Description

Biomass shape memory polyurethane material and preparation method thereof

The present invention relates to a polymeric material, particularly a biocompatible polyurethane material having a shape memory effect.

The shape memory effect was first discovered by the University of Illinois in 1951, while Japan Nakagawa defined the shape memory behavior in 1959: the material is susceptible to the gradual recovery of the previous mechanical behavior. The US Naval Measurement Laboratory discovered in 1965 that Ni-Ti alloys have shape memory behavior, and currently commercial products of shape memory alloys include eyeglass frames, bras, and the like. Japan's Mitsubishi Heavy Industries discovered in 1990 that polyurethane also has shape memory behavior.

Shape memory materials are materials that are capable of changing their outer shape under the influence of external stimuli. If it is a shape change due to a temperature change, it is a shape memory effect caused by heat.

Existing polyurethane materials do not have good shape recovery performance when used at low temperatures. When existing polyurethane materials are used in medical equipment fields, such as human side wood materials, they exhibit a phase change lower than human body temperature, and thus are not suitable for products. Practical application. These polyurethanes are significantly limited in their temperature application range.

In addition, the current polyurethane composition materials are not derived from plant biomass, have no biodegradability and biocompatibility characteristics, and therefore are incapable of being applied to medical equipment fields, and it is difficult to increase the added value of products.

Since the existing polyurethane materials still have many problems in the field of application to medical equipment, the present invention provides a shape memory polyurethane material having an elevated phase transition temperature while having a temperature application range of at most 80 °C. And the composition of the polyurethane material contains biomass-derived PLA (polylactic acid).

The preparation method of the raw shape memory polyurethane material of the present invention comprises the following steps:

(a) preparing PLA: preparing one or more biomass-derived PLA;

(b) preparing a prepolymer: reacting the PLA of step (a) with a diisocyanate at a molar ratio of NCO/OH of from about 1.0 to 1.4 to form an isocyanate-terminated prepolymer;

(c) Preparation of a biomass shape memory polyurethane material: The prepolymer in step (b) is reacted with one or more diol chain extenders to form a green shape memory polyurethane material.

The PLA system can be made from a monomer which is cracked from the recovered PLA.

The diisocyanate may be an aromatic diisocyanate or an aliphatic diisocyanate, and the aliphatic diisocyanate may be HDI (hexamethylene diisocyanate) or LDI (2,6-diisocyanate, L-Lysine Diisocyanate). The aromatic diisocyanate may be MDI (diphenylmethane-4,4'-diisocyanate, 4,4 Diphenylmethane diisocyanate) or TDI (2,4-toluene diisocyanate).

NCO/OH can be in the molar ratio of about 1.1.

The PLA may be linear and have a molecular weight of 2,000 to 4,000 g/mol.

The diol chain extender may have a molecular weight of from about 90 to about 400 g/mol.

The diol chain extender can be 1,4-butanediol or 1,6-hexanediol.

In the preparation method of the present invention, a catalyst may be used to promote the reaction, and the catalyst is tin diacetate, tin dioctoate, tin dilaurate or an aliphatic dialkyl tin salt. The catalyst may preferably be dibutyltin dilaurate (DBTDL). The total amount of catalyst added may be from about 0.01 to 1 wt% of the total amount of the polyurethane material.

The invention further provides a biomass shape memory polyurethane material comprising a polyurethane having the formula:

among them,

PLA is

R is .

Preferably, R is .

The invention provides a biomass shape memory polyurethane material comprising a polyurethane based on PLA (polylactide), the biomass shape memory polyurethane material comprising a polyurethane having the following formula:

among them,

PLA is

R is .

Preferably, R is

The preparation and properties of this PLA are illustrated in the subsequent examples.

The preparation method of the raw shape memory polyurethane material of the present invention comprises the following steps:

(a) Preparation of PLA: One or more of the biomass-derived PLAs are prepared, which are preferably prepared by cleavage of the monomer from the recovered PLA, which has biodegradability and biocompatibility characteristics. PLA is the best physical property of all biodegradable materials. PLA is chosen because the chemical formula has reactive difunctional groups at both ends, hydroxyl and alcohol groups, so it has a modified terminal functional group application, plus PLA. The source of the recovered PLA container fragments is in line with the green demands of environmentally friendly recycling.

Preferably, the PLA is linear and has a molecular weight of 2,000 to 4,000 g/mol. The molecular structure is designed, and the heat distortion temperature of the memory material depends on the soft segment of the polyurethane, and the suitable soft segment material is There are two types of polyether polyols and polyester polyols. According to the present invention, linear polyether diols and polyester diols are selected in the molecular weight range of 2,000 to 4,000.

(b) Preparation of a prepolymer: The PLA of step (a) is reacted with a diisocyanate at a molar ratio of NCO/OH of from about 1.0 to 1.4 to form an isocyanate-terminated prepolymer.

The diisocyanate may be an aromatic diisocyanate or an aliphatic diisocyanate. The aromatic diisocyanate may be MDI (diphenylmethane 4,4'-diisocyanate, 4,4 Diphenylmethane diisocyanate) or TDI (2,4-toluene diisocyanate). The aliphatic diisocyanate may be HDI (hexamethylene diisocyanate) or LDI (2,6-diisocyanate, L-Lysine Diisocyanate).

In the present invention, an aliphatic diisocyanate is preferred. Polyurethanes formed by aliphatic diisocyanates (such as HDI) are more flexible, and have a higher rate of deformation recovery, faster speed, and greater tensile effect upon heating, compared to temperature-changing shape memory materials, such as aromatic diisocyanates. MDI has an aromatic ring, and the polyurethane material has a relatively slow recovery speed and a high material rigidity.

In the present invention, a molar ratio of NCO/OH of about 1.0 to 1.4 is preferred, wherein a molar ratio of NCO/OH of about 1.1 is preferred, and an excess of NCO tends to cause excessive by-products, and the purity of the product is lowered, and The shape memory recovery effect can be adjusted using different NCO/OH molar ratios.

The reaction rates of the two isocyanato groups in the diisocyanate are also different (K1 and K2). The reaction rate is significantly affected by temperature, but at temperatures above 70 ° C, regardless of the type of diisocyanate, there is high reactivity.

(c) preparing a raw shape memory polyurethane material: reacting the prepolymer in step (b) with one or more diol chain extenders to form a green shape memory polyurethane material, the molecular weight of the diol chain extender being about 90 to about 400 g/mol.

Typical polyester chain extenders in the present invention are 1,4-butanediol, 1,6-hexanediol, and polytetramethylene ether glycol, wherein the chain extender suitable for the present invention is 1,4 - Butylene glycol or 1,6-hexanediol.

Preferably, the catalyst can be used to promote the reaction in the process of the present invention. Suitable catalysts are tin diacetate, tin dioctoate, tin dilaurate or aliphatic dialkyl tin salts. The preferred catalyst is dilauric acid. Dibutyltin (DBTDL), in the present invention, the total amount of the catalyst added is about 0.01 to 1 wt% of the total amount of the polyurethane material.

Since the biomass-derived PLA has biodegradability and biocompatibility characteristics, the product of the present invention has potential for application in the field of medical devices. The raw material shape memory polyurethane material developed by the invention can be used as a secondary wood product for orthopedics, and after being made into a secondary wood, the thermoplasticity of the material can be used for the patient's elbow, and the polyurethane material can be plasticized. The flexibility makes it conform to the pre-fixed part, and when the injury wants to be disassembled, the change of the temperature of the material can be easily restored to a flat shape, which facilitates disassembly and re-forming.

The advantages of the biomass shape memory polyurethane material of the present invention are as follows:

1. The traditional secondary wood board is made of PCL. Because of its high price and need to be imported from abroad, it is another burden for patients and physiotherapists. The polyurethane material developed by the present invention is relatively cheaper and simple to manufacture, and can be controlled by foreign raw materials.

2. The shape recovery rate of the polyurethane material of the invention is good, up to 90%, and the temperature of the heating and molding type is lower than 60 ° C, the patient can use the hair dryer for household to achieve the purpose of self-adjustment, which can be said to be practical. high.

3. The auxiliary wood made of the polyurethane material of the invention does not need to be shaped like a traditional wood protection product which needs to be immersed in hot water higher than 100 ° C, so that the patient can be accidentally burnt and the physiotherapist is in use. Add a lot of convenience.

For material selection, content ratio and material preparation, please refer to the following examples: [Example 1] Preparation of PLA

The synthetic preparation steps of the biomass-derived PLA are summarized as follows in the first figure:

1. The low molecular weight PLA (Mw: 1,000) degraded by the recovered PLA was weighed and placed in a four-port reactor, and dehydrated and polymerized by a vacuum dewatering method to form a PLA oligomer.

2. Add a chain extender of 1,4-BDO while adding a catalyst, and carry out reaction polymerization under a high vacuum environment system while maintaining a reaction temperature of 80 °C.

[Example 2] Determination of the properties of PLA

The product of Example 1 was a polymer of PLA and 1,4-BDO. The functional group was determined by FT-IR, the molecular weight was measured again, and the structure (hydrogen number) was finally determined by NMR. Please refer to the second, third and fourth figures for the analysis results.

Referring to the second graph, the results of FT-IR measurement showed the strong absorption peak near 1757cm ^-1 is an ester group of the C = O absorption characteristics, 1190 cm ^-1 an absorption peak near the CO absorption characteristics ether group Therefore, these two points can prove that the structure of -COO- exists. The absorption peak between 2830 and 3000 cm ^-1 is the characteristic absorption of CH. There are two H structures in PLA, and there is only one PEG. Pure PLA has two CH vibration absorptions at 2999 cm ^-1 and 2948 cm ^-1 , indicating the presence of -CH ₃ and -CH, respectively. On the grafted product map, there are three kinds of vibration absorptions of 2996 cm ^-1 , 2945 cm ^-1 and 2878 cm ^-1 , respectively , which indicate the presence of -CH ₃ , -CH ₂ and -CH, and the copolymer is more than PLA. The absorption of a characteristic of -CH ₂ also proves that the grafting of PLA and PEG does occur.

The molecular weight of the polylactic acid monomer (Mw: 90), after determining the presence of the functional group by FT-IR, and then testing the molecular weight of the polymer to test whether a graft reaction occurs, please refer to the third figure, the GPC test results It is shown that the molecular weight of the polymer is about 3,000 and the molecular weight distribution (PDI) is about 1.02. This result proves that the molecular weight distribution of the product is fairly average, and in the GPC analysis results, no other polymer is found except the solvent peak. Peak, so this figure can prove that the polymer is the molecular structure product originally designed.

Please refer to the fourth figure to identify the structure of the product by NMR. After analysis by NMR instrument, the structure is judged by hydrogen number. The results show that the corresponding group hydrogen number is consistent with the molecular structure originally designed. evidence.

[Example 3] Preparation of Biomass Shape Memory Polyurethane Material

(1) According to the formula ratio (isocyanate, PLA), an appropriate amount of the PLA polyol mixture was placed in a four-port reactor, and the temperature was raised to 70 ° C under nitrogen, and the stirring speed was fixed at 200 rpm for about 2 hours.

(2) An appropriate amount of isocyanate is dissolved in THF, and slowly dropped into the reactor. After the completion of the dropwise addition, the mixture is stirred and mixed for a suitable period of time, and then the reaction temperature is raised to 80 ° C to start the reaction.

(3) After the above prepolymer is thoroughly mixed, a solvent of 1 time is added, and the fixing temperature is stirred at 80 ° C to sufficiently mix the prepolymer with THF.

(4) An appropriate amount of chain extender was taken, slowly dropped into the reaction system, and allowed to react for 2 hours, and the absorption peak of NCO was measured by FT-IR to confirm the completion of the reaction.

(5) The synthesized PU colloid is decompressed to remove the bubbles that are driven by the agitation, and then the gel is poured into a suitable mold by a small amount of the reaction, and a vacuum of 70 ° C is placed. After 48 hours in the oven, a small amount of residual THF and water were removed, and after drying, the properties were further analyzed.

[Example 4] Thermal property analysis of raw material shape memory polyurethane material

The thermal property analysis results of the biosonic shape memory polyurethane material are shown in Figure 5. The fifth graph is the analysis result of the thermal differential scanning card meter (DSC). It can be shown from the analysis results that the Tg temperature of the material is 53.7 °C. The results of this analysis are also consistent with the operating temperature at which the shape memory deformation of the material of the present invention requires less than 60 °C.

[Example 5] Tensile strength of polyurethane synthesized by different polyesters and polyethers

The reaction speed of TDI is faster, but the strength of polyurethane formed is lower, the recovery speed of deformation is slow, the memory effect is not good, and the reaction speed of MDI is moderate. The strength of polyurethane formed is high, the recovery speed of deformation is fast, and the memory effect is good. This is because the molecular structure of MDI is more regular than TDI, like a symmetric type of diisocyanate (such as HDI), which facilitates the crystallization and phase separation of the soft and hard segments, so that a better memory effect can be obtained.

[Example 6] Recovery rate test of biomass shape memory polyurethane material

The recovery rate test of the present invention is to perform a bending test under the different water bath temperatures of the first-line type test piece to investigate the shape memory recovery effect of the material. Please refer to the sixth figure for a schematic diagram of the bending test of shape memory materials. Sample preparation: A test piece of approximately 5 cm in length, 1 cm in width, and 0.3 cm in height was prepared.

The test procedure is to first immerse the test piece in hot water of 60 degrees → the test piece is softened and then bent and shaped → then immerse the curved test piece in cold water at room temperature → wait for 1~3 seconds to finalize → The immersed test piece is immersed in hot water immersed in 60 degrees without external force, so that it naturally returns to → after 3~8 seconds, the test piece is completely still after moving → take out and measure the test piece recovery angle and Make a difference comparison before bending. The recovery rate can be measured.

Recovery ratio (R)=

Angle of recovery / angle of original bending × 100%

Final recoverable ratio (Rf): The recovery rate at the end of the test.

The invention uses the biomass-derived PLA as a substrate to prepare a polyurethane material with shape memory behavior. The minimum recovery temperature of the material is 50 ° C. When the polymer transition temperature is 65 ° C, the deformation recovery rate of the material is about 90%.

The first figure is a synthetic preparation flow chart of the biomass-derived PLA of the present invention.

The second graph is the result of FT-IR measurement of the biomass-derived PLA of the present invention.

The third graph is the molecular weight measurement result of the biomass-derived PLA of the present invention.

The fourth graph is the result of NMR analysis of the biomass-derived PLA of the present invention.

The fifth figure is the result of thermal property analysis of the biomass shape memory polyurethane material of the present invention.

The sixth figure is a schematic diagram of the recovery rate test of the biomass shape memory polyurethane material of the present invention.

Claims (14)

A method for preparing a raw shape shape memory polyurethane material, comprising the steps of: (a) preparing PLA: preparing one or more kinds of biomass-derived PLA; (b) preparing a prepolymer: the step (a) of PLA and diisocyanate Forming an isocyanate-terminated prepolymer with NCO/OH in a molar ratio of about 1.0 to 1.4; and (c) preparing a biomass shape memory polyurethane material: the prepolymer in step (b) and one or more The alcohol chain extender reacts to form a biomass shape memory polyurethane material. The preparation method according to claim 1, wherein the PLA is prepared by pulverizing the recovered PLA into a monomer. The preparation method according to claim 2, wherein the diisocyanate is an aromatic diisocyanate or an aliphatic diisocyanate. The preparation method according to claim 3, wherein the aliphatic diisocyanate is HDI (hexamethylethylene diisocyanate) or LDI (2,6-diisocyanate, L-Lysine Diisocyanate). The preparation method according to claim 3, wherein the aromatic diisocyanate is MDI (diphenylmethane-4,4'-diisocyanate, 4,4 Diphenylmethane diisocyanate) or TDI (2,4-toluene diisocyanate). ). The preparation method according to any one of claims 1 to 5, wherein the NCO/OH is in a molar ratio of about 1.1. The preparation method according to claim 6, wherein the PLA is linear and has a molecular weight of 2,000 to 4,000 g/mol. The process of the invention of claim 7, wherein the diol chain extender has a molecular weight of from about 90 to about 400 g/mol. The preparation method of claim 8, wherein the diol chain extender is 1,4-butanediol or 1,6-hexanediol. The preparation method according to claim 9, wherein the catalyst is used to promote the reaction, and the catalyst is tin diacetate, tin dioctoate, tin dilaurate or an aliphatic dialkyl tin salt. The preparation method of claim 10, wherein the catalyst is dibutyltin dilaurate (DBTDL). The preparation method according to claim 11, wherein the total amount of the catalyst added is about 0.01 to 1 wt% of the total amount of the polyurethane material. A biomass shape memory polyurethane material comprising a polyurethane having the formula: Among them, PLA is R is . The raw material shape memory polyurethane material according to claim 13 wherein R is .