Abstract:
A dendron with hydrophobic functional of end group, a polyurethane with the dendron, and producing methods thereof are disclosed. The dendron with hydrophobic functional of end group in the polyurethane systems, and the honeycomb-like structure thin films were obtained by a breath-figure process. The structures of dendron and dendritic side-chain polyurethanes are respectively expressed in the following. Therein, the end-groups (R) of the dendron are long alkyl chains or perfluoroalkyl derivatives.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    This invention relates to a dendron with hydrophobic functional of end group, a polyurethane with the dendron, and producing methods thereof, and more particularly, the end group of the dendron includes alkyl chains or perfluoroalkyl chains, such as C 10 ˜C 18  or perfluoroalkylethyl derivatives with more-than-four carbons. 
         [0003]    2. Description of the Prior Art 
         [0004]    In the recent years, there are more than 2000 relevant literatures about dendritic molecular chemistry. Dendrimer has a highly regular branched structure. By the step reaction, the molecular size thereof could be precisely controlled and it could be diversified. Buhleier et al. used addition and reduction reaction of acrylonitrile to produce dendrimer-like branched amines, i.e. hyperbranched polymer, in 1978. Tomalia et al. first published nano-dendritic poly(amidoamine) dendrimer in 1984 and also have established the record of earliest commercialization. The dendrimer consists of three basic structures including (1) core, (2) repeating unit, and (3) periphery group. The synthesis path could be classified by the growth direction into divergent type and convergent type. 
         [0005]    In the prior art, for skipping the complicated steps of protection and dis-protection, improving productivity, and efficiently extending the generation growth, bifunctional build unit IDD (4-isocyanato-4′(3,3-dimethyl-2,4-dioxo-azetidino)diphenylmethane) is taken as the base. A series of regular dendrimers of derivatives of malonamide and urethane are developed by using the high reactivity of isocyanate and selective reactivity of azetidine-2,4-dione to perform alternating synthesis reaction with different alcohols and amines. The flow chart is shown in  FIG. 1 . 
         [0006]    In addition, the side-chain dendrimer could be regarded as a structure copolymer of linear polymer and dendrimer. In the patent by Tomalia et al. in 1987, a dendrimer with a main chain of line polyethylenimine (PEI) is first mentioned. According to the literature, the side-chain dendrimer could be applied in the fields of self-assembly, nano leads of mono-molecule, light-emitting material, catalyst, and so on. 
       SUMMARY OF THE INVENTION 
       [0007]    The invention leads a long segment of alkyl chain and perfluoroalkyl chain in a dendritic structure. There is the effect of Van der Waal force between the molecules. In addition, the long alkyl chain or the perfluoroalkyl chain are constrained and bound together using the structure of dendron to form a sausage-like dendron, the structure of which is hydrophobic. On the other hand, the dendron has a urea/malonamide structure with strong hydrogen bond in the interior. Besides, the hydrogen bond interaction and the Van der Waal force in the respective interior and exterior of the dendron increase as the generation of the dendron increases. 
         [0008]    After decyclization and addition reaction, the invention produces dendrons of different generations into a polyurethane system, so as to form a series of polyurethanes with side-chain regular dendron. Because of the hydrogen bond and the Van der Waal force in the respective interior and exterior of the dendron, the polyurethane with side-chain regular dendron could be produced with porosity using the breath figure method. Further, for increasing the practicability of the material, the invention controls the assembly of flexible and hard chain segments of the polyurethane with side-chain regular dendron so as to enhance the mechanical property of the porous film. 
         [0009]    A scope of the invention is to lead dendron into a side chain of polyurethane, including a structure expressed by the following formula: 
         [0000]    
       
                 
         
             
             
         
       
     
         [0010]    Therein, R 1  represents diisocyanate, and R 2  represents polyol. 
         [0011]    The diisocyanate could be methylene di-p-phenyl diisocyanate (MDI), 1,6-hexamethylene diisocyanate (HDI), or isophorone diisocyanate (IPDI). The polyol could be polypropyl glycol (PPG), polycaprolactone (PCL), and polytetramethylene ether glycol (PTMEG). 
         [0012]    According to an embodiment, when R 1  is MDI and R 2  is PPG, the compound for the formula (I) could be expressed by the following formula: 
         [0000]    
       
                 
         
             
             
         
       
     
         [0013]    According to another embodiment, when R 1  is HDI and R 2  is PPG, the compound for the formula (I) could be expressed by the following formula: 
         [0000]    
       
                 
         
             
             
         
       
     
         [0014]    According to another embodiment, when R 1  is IPDI and R 2  is PPG, the compound for the formula (I) could be expressed by the following formula: 
         [0000]    
       
                 
         
             
             
         
       
     
         [0015]    According to another embodiment, when R 1  is MDI and R 2  is PCL, the compound for the formula (I) could be expressed by the following formula: 
         [0000]    
       
                 
         
             
             
         
       
     
         [0016]    According to another embodiment, when R 1  is MDI and R 2  is PTMEG, the compound for the formula (I) could be expressed by the following formula: 
         [0000]    
       
                 
         
             
             
         
       
     
         [0017]    Films with honeycomb porosity are made of the above film material by the breath figure method. Because of the increase of roughness, the films can be hydrophobic, even superhydrophobic. 
         [0018]    The advantage and spirit of the invention may be understood by the following recitations together with the appended drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE APPENDED DRAWINGS 
         [0019]      FIG. 1  is a schematic diagram illustrating the flow chart of the regular dendrimers in the prior art. 
           [0020]      FIG. 2  is a flow chart of the process of leading the dendron into the side chain of the polyurethane. 
           [0021]      FIG. 3  is a flow chart of the reaction process of the unit IDD with selectivity. 
           [0022]      FIG. 4  is a flow chart of the reaction process of dendrons of different generations. 
           [0023]      FIG. 5  is a flow chart of the reaction process of the dendritic chain extender to be used in the polyurethane system. 
           [0024]      FIG. 6  is a schematic diagram of the dendron. 
           [0025]      FIG. 7  is a  1 H NMR spectrogram of the dendritic chain extender in  FIG. 5 . 
           [0026]      FIG. 8  is a  1 H NMR spectrogram of the dendritic chain extender with C 8 F 17 . 
           [0027]      FIG. 9  is an AFM diagram of a film made of the polyurethane with MDI and PPG. 
           [0028]      FIG. 10  is an AFM diagram of a film made of the polyurethane with HDI and PPG. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0029]    According to an embodiment, a dendron is led to a side chain of the polyurethane of the invention, expressed by the following formula: 
         [0000]    
       
                 
         
             
             
         
       
     
         [0030]    Therein, R 1  represents diisocyanate, and R 2  represents polyol. 
         [0031]    The diisocyanate could be methylene di-p-phenyl diisocyanate (MDI), 1,6-hexamethylene diisocyanate (HDI), or isophorone diisocyanate (IPDI). The polyol could be polypropyl glycol (PPG), polycaprolactone (PCL), and polytetramethylene ether glycol (PTMEG). 
         [0032]    The process of leading the dendron into the side chain of the polyurethane could be illustrated by the flow chart of  FIG. 2 . The process is described in detail by the following embodiments. 
       Embodiment I 
     The Synthesis of Dendron 
       [0033]    In the embodiment, the reaction process of the unit IDD with selectivity is illustrated by the flow chart of  FIG. 3 . 
         [0034]    The IDD is used to react with stearyl alcohol. Then, primary amine is used to perform decyclization reaction on azetidine-2,4-dione. By the step-by-step synthesis steps, dendrons of different generations are synthesized. The reaction process is illustrated by the flow chart of  FIG. 4 . 
         [0035]    The above dendron could be made by the following steps. First, bifunctional build unit IDD is dissolved in tetrahydrofuran (THF) to form a first solution. Alcohol is added into the first solution at 70 degrees in Celsius with aerating nitrogen of gas for 4 hours. After the reaction ends, the first solution is dropped into methanol for precipitation and stirred at 70 degrees in Celsius for 6 hours. A first product is collected from the solution by exhaust filtering. The first product is then dried to obtain a first intermediate (G- 0 . 5 ). 
         [0036]    Next, the first intermediate (G- 0 . 5 ) is disposed a reaction flask to be dissolved in dehydrated tetrahydrofuran to form a second solution. Nitrogen of gas is aerated in the second solution. The second solution is stirred and slowly added with diethylenetriamine (DETA) at 70 degrees in Celsius. The second solution is kept in reaction for 3 hours after a second product starts being precipitated. Afterwards, the second solution is cooled to the room temperature, washed with tetrahydrofuran, and dried by exhaust filtering so as to obtain a dendrimer (G- 1 ). 
         [0037]    Then, the dendrimer (G- 1 ) is mixed with dehydrated tetrahydrofuran to form a third solution. The third solution is stirred with aerating nitrogen of gas at 75 degrees in Celsius. After the dendrimer (G- 1 ) has been dissolved, the bifunctional build unit IDD is added in the third solution for reaction for 4 hours. A part of the tetrahydrofuran is drawn. The third solution is dropped into methanol for precipitation; a second intermediate (G- 1 . 5 ) is obtained by exhaust filtering and then drying. 
         [0038]    Afterwards, the above steps are repeated for producing a third intermediate (G- 2 . 5 ) and a fourth intermediate (G- 3 . 5 ). At last, the first intermediate (G- 0 . 5 ), the second intermediate (G- 1 . 5 ), the third intermediate (G- 2 . 5 ), and the fourth intermediate (G- 3 . 5 ) are dissolved into dehydrated tetrahydrofuran and mixed with N-(3-aminopropyl)diethanolamine (APDEA) so as to form a fourth solution. The fourth solution is kept in reaction under aerating nitrogen of gas at 75 degrees in Celsius for 48 hours. After the intermediate (G- 1 . 5 ) have completely reacted, the fourth solution is dropped into methanol for precipitation and washing incompletely-reacted APDEA out. After the solution has been stirred for 6 hours, the dendron is then obtained by exhaust filtering and then drying. 
         [0039]    For leading the dendron into the system of the polyurethane, a chemical modification is required. In the embodiment, primary amine and azetidine-2,4-dione are used to perform decyclization reaction to synthesize the intermediate (G- 1 . 5 )-glycol with functional group of glycol, so as to be used as chain extender in the polyurethane system. The above process is illustrated in the flow chart of  FIG. 5 . 
         [0040]    Similar to the synthesis of dendron of alkyl chain, derivative relative to perfluoroalkylethyl ethyl alcohol is led to make the end of the dendron with perfluorooctyl ethyl group. The dendron has low surface energy, so films made of the dendron can be superhydrophobic. The dendron is schematically illustrated in  FIG. 6 . 
       Embodiment II 
     The Synthesis of the Compound (I-A) 
       [0041]    Preparing raw materials of MDI and PPG depends on the ratio of flexible and hard chain segments. MDI is heated at 50 degrees in Celsius to melt; the clear portion of the upper liquid is taken. PPG is dehydrated in vacuum in an oven, then heated to 80 degrees in Celsius, and exhausted for 6 hours. Next, MDI and PPG are dissolved in dimethyl formamide (DMF) with aerating nitrogen of gas at 60 degrees in Celsius for half an hour for reaction. Then, the dendritic compound (G- 1 . 5 )-glycol is added in the solution. Dibutyltin dilaurate is taken as catalyst. The solution is heated up to 80 degrees in Celsius for 3.5 hours for reaction. After the reaction ends, the solution is poured onto a disk of Teflon to be disposed in an oven for removing solvent and forming films. 
       Embodiment III 
     The Synthesis of the Compound (I-B) 
       [0042]    Preparing raw materials of HDI and PPG depends on the ratio of flexible and hard chain segments. HDI is used without purification. PPG is dehydrated in vacuum in an oven, then heated to 80 degrees in Celsius, and exhausted for 6 hours. Next, HDI and PPG are dissolved in DMF with aerating nitrogen of gas at 60 degrees in Celsius for half an hour for reaction. Then, the dendritic compound (G- 1 . 5 )-glycol is added in the solution. Dibutyltin dilaurate is taken as catalyst. The solution is heated up to 80 degrees in Celsius for 3.5 hours for reaction. After the reaction ends, the solution is poured onto a disk of Teflon to be disposed in an oven for removing solvent and forming films. 
       Embodiment IV 
     The Synthesis of the Compound (I-C) 
       [0043]    Preparing raw materials of IPDI and PPG depends on the ratio of flexible and hard chain segments. IPDI is used without purification. PPG is dehydrated in vacuum in an oven, then heated to 80 degrees in Celsius, and exhausted for 6 hours. Next, IPDI and PPG are dissolved in DMF with aerating nitrogen of gas at 60 degrees in Celsius for half an hour for reaction. Then, the dendritic compound (G- 1 . 5 )-glycol is added in the solution. Dibutyltin dilaurate is taken as catalyst. The solution is heated up to 80 degrees in Celsius for 3.5 hours for reaction. After the reaction ends, the solution is poured onto a disk of Teflon to be disposed in an oven for removing solvent and forming films. 
       Embodiment V 
     The Synthesis of the Compound (I-D) 
       [0044]    Preparing raw materials of MDI and PCL depends on the ratio of flexible and hard chain segments. MDI is heated at 50 degrees in Celsius to melt; the clear portion of the upper liquid is taken. PCL is dehydrated in vacuum in an oven, then heated to 80 degrees in Celsius, and exhausted for 6 hours. Next, MDI and PCL are dissolved in DMF with aerating nitrogen of gas at 60 degrees in Celsius for half an hour for reaction. Then, the dendritic compound (G- 1 . 5 )-glycol is added in the solution. Dibutyltin dilaurate is taken as catalyst. The solution is heated up to 80 degrees in Celsius for 3.5 hours for reaction. After the reaction ends, the solution is poured onto a disk of Teflon to be disposed in an oven for removing solvent and forming films. 
       Embodiment V 
     The Synthesis of the Compound (I-E) 
       [0045]    Preparing raw materials of MDI and PTMEG depends on the ratio of flexible and hard chain segments. MDI is heated at 50 degrees in Celsius to melt; the clear portion of the upper liquid is taken. PTMEG is dehydrated in vacuum in an oven, then heated to 80 degrees in Celsius, and exhausted for 6 hours. Next, MDI and PTMEG are dissolved in DMF with aerating nitrogen of gas at 60 degrees in Celsius for half an hour for reaction. Then, the dendritic compound (G- 1 . 5 )-glycol is added in the solution. Dibutyltin dilaurate is taken as catalyst. The solution is heated up to 80 degrees in Celsius for 3.5 hours for reaction. After the reaction ends, the solution is poured onto a disk of Teflon to be disposed in an oven for removing solvent and forming films. 
         [0046]    In addition, the  1 H NMR spectrogram of the chain extender in  FIG. 5  is illustrated in  FIG. 7 ; the  1 H NMR spectrogram of the chain extender with C 8 F 17  is illustrated in  FIG. 8 . A film made of the polyurethane with MDI and PPG or with HDI and PPG is porous, shown in  FIGS. 9 and 10 . 
         [0047]    With the example and explanations above, the features and spirits of the invention will be hopefully well described. Those skilled in the art will readily observe that numerous modifications and alterations of the device may be made while retaining the features and spirit of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.