衣康酸研究進(jìn)展

1、衣康酸研究進(jìn)展 These polyesters were designed for drug delivery One-Step Syntheses of Photocurable Polyesters Based on a Renewable ResourceMacromolecules 2010, 43, 96609667 this is the first use of IA in thermally synthesized branched polyesters, the first enzymatic synthesis of itaconate-based polymers, a

2、nd the first use of itaconate-based materials in combination with the photoinitiator DEAPBiocompatibility and biodegradation are requisites in order to minimize the stress that isimposed upon living systems by the material反應(yīng)條件 heat (120-150 C) and vacuum without catalysts or coreagents IA was combin

3、ed with adipic acid (AA) and trimethylolpropane (TMP三羥甲基丙烷) in order to obtain branched, photocurable polyesters A similar prepolymer was synthesized by the polyesterification of IA, succinic acid (SA),and sorbitol. Additionally, dimethyl itaconate (DMI) is compatible with enzymatic polyester synthe

4、sis, catalyzed by Novozyme 435（諾維信脂肪酶） -Lipa se B f romCandida antarctic a(C A L B ).Materials 1-3Prepolymers 1, 2, and 3(PP1, PP2, and PP3) contained IA, AA, and TMP in ratios of1:0:1, 1:3:4, and 1:9:10, respectively. The monomers were heated only to the extent of cross-linking that would create ol

5、igomeric prepolymers; thermal cross-linking was avoidedin order to obtain soluble prepolymers. The molecular weights of these oligomers were relatively small, with PP1, PP2, and PP3 having ÆMn æ values of 1140, 2200, and 1170 g/mol (Table 2). Additionally, all of the prepolymers were amorp

6、hous, with glass transition ( Tg) temperatures ranging from -28.8 to -7.4 C. The inclusion of larger amounts ofAA caused lowerTg values, most likely due to the resulting decrease in cross-linking densitya photoinitiator that is commonly used in biomaterialsDEAP 光引發(fā)劑2,2-二乙氧基苯乙酮(DEAP) Material 4The sy

7、nthesis of prepolymer 4 (PP4) was very similar to those of the TMP-based materials (Scheme 2). Again, the monomers were heated only to the extent of cross-linkingthat would create oligomeric prepolymers. PP4 was amor-phous (T g = 39.8 C) withÆMnæ = 940 g/mol (Table 2).Additionally, as sorb

8、itol contains six hydroxyl groups, thisprepolymer should be very hydrophilic when compared toPP1 - PP3. This hypothesis was supported by the fact thatPP4 was soluble in water, along with other polar organicsolvents (DMSO, DMF, methanol, ethanol, etc.); PP1 - PP3were soluble in organic solvents that

9、were much more nonpolar, such as chloroform and methylene chloride.PP5 andPP6, both homopolymers, were designed by combining DMI with CHDM and PEG, respectively. In the presence of 10 wt % CALB, polymerizations occurred at 90 C for 48 h under a partial vacuum for the final 46 h. PP5 and PP6 achieved

10、 molecular weights of 2030 and 6650 g/mol,respectively (Table 2). The choice of diol had a large impact on the thermal properties. PP5, composed of the cyclic diol CHDM, had the largest T g of all linear materials (-25.4 C).The T gof PP6 was -50.8 C, much lower due to the use of PEG as the diol.Mate

11、rial 7.When PP5 and PP6 were cured, the resulting polymers were brittle due to the high-cross-linking density which is due to each repeat unit containing a site for radical cross-linking. We hope to further increase the flexibility of itaconate-based polyesters by producing a copolymer in anattempt

12、to dilute the cross-linking sites. In order to accom-plish this goal, AA was included in the monomer feed; DMI: AA:MPD = 1:3:4. The synthesis was identical to the proce-dure used for PP5 and PP6. The inclusion of AA caused a large increase in the molecular weight of the prepolymer, which obtained &#

13、198;Mn æ = 11 900 g/mol (Table 2). TheTgof PP7, -57.6 C, was again low due to the choice of the diol. The branched structure of MPD prevented efficient packing,which resulted in a low TgMPD 3 - 甲基-1 ，5 - 戊二醇彈性模量 極限拉伸應(yīng)力 斷裂應(yīng)變 However, by increasing the amount of AA in the monomerfeed, the resulti

14、ng polyesters were weaker and much moreflexible. Material 2 (IA:AA = 1:3) displayed YM, UTS, andRS values of 2 MPa, 1 MPa, and 65%, respectively; material3 (IA:AA = 1:9) was far more elastic, with a YM of 0.2 MPA,an UTS of 0.2 MPa, and a RS of 200%. Between materials1 -3, the YM varied over 3 orders

15、 of magnitude, the UTS varied over 2 orders of magnitude, and the RS varied over 1 order of magnitude The contact angle values for materials 1, 2, and 3 were 42.7 ,52.7 , and 64.5 Prepolymer 4 was cured based on the process described for materials 1-3. Succinic acid was included in the monomer feed

16、of material 4 in an attempt to dilute the cross-linking density and design a flexible polyester. This goal was real-ized, as polymer 4 displayed a YM, UTS, and RS of approxi-mately 11 MPa, 2 MPa, and 120%, respectively (Table 3). In the hydrated state, these values changed to 0.88 MPa (YM), 0.11 MPa

17、 (UTS), and 23% (RS). Material 4 experienced thegreatest loss of mechanical properties as a result of hydra-tion. We believe that these results are due to the fact that polymer 4 is best able to interact with water because of the large number of free hydroxyl groups from sorbitol and the presence of

18、 free acids; in a very hydrated state, this polymer becomes much softer and more flexible. In comparison, materials 1 - 3 do not experience as great a loss in their mechanical properties due to their more hydrophobic repeat unitsPolymer 4 was expected to display significant hydrophilic character due

19、 to the pres-ence of six hydroxyl groups in sorbitol. This hypothesis was verified when the contact angle for material 4 was deter-mined to be 29.4 (Table 3). The soluble portion of this polyester was surprisingly large at 47.6% The degree of swelling in water for polyester 4 was 14.7%. The use of s

20、uch a hydrophilic monomer facil-itated the design of a polymer with many free acids and alcohols that experienced at least twice as much swelling in water as materials 1-3Materials 5 and 6. PP5 and PP6, both homopolymers, were designed by combining DMI with CHDM and PEG, respectively. In the presenc

21、e of 10 wt % CALB, polymerizations occurred at 90 C for48 h under a partial vacuum for the final 46 h. PP5 and PP6 achieved molecular weights of 2030 and 6650 g/mol, respectively (Table 2). The choice of diol had a large impact on the thermal properties. PP5, composed of the cyclic diol CHDM, had th

22、e largest T g of all linear materials (-25.4 C).The T g of PP6 was -50.8 C, much lower due to the use of PEG as the diol. Polyester 5 was composed of DMI and CHDM, a small andcyclic diol. As such, thermoset 5 is very strong and very brittle; its YM, UTS, and RS values are 380 MPa, 16.5 MPa, and 6%,

23、respectively (Table 3). Since this polymer is linear and hydrophobic, it displays a very similar mechanical pro-file when it is hydrated. However, polyester 6 is based on a PEG macromonomer , which provides more space between cross-link i ng sites. The resul t i s a material that is moreflexible tha

24、n the o th er homopolym ers. The Y M, UTS, and R S values for pol ymer 6 are app roximately 7.5 M Pa , 2.7 MP a, and 45%, res pectivel y. Th is polymer was u ni que in ter ms of i ts hydrated mech anical profile; the YM in-creased b y 8 5% (1 3.85 MP a), the UTS d ec reased by 64% (1 MP a), and the

25、RS d ecr e ased by 73% (12%). Current studies are attemptin g to under stand the differen c e between the mech anica l p roper t ie s o f the dr y state and those of the hydrated state. Polyester 5 was expected to be very hydrophobic due to the cyclic hydrocarbon interior of CHDM. This hypothesis wa

26、s validated by the contact angle (79.5 ) and water swelling results (6.1%) Polyester 6 was thought to be very hydrophilic since a large PEG diol (400 g/mol) was employed as a macromonomer. The degree of swelling in water, 60%, supported this expectation; material 6 swelled at least 4 times as much a

27、s any of the other polyesters in this study. However,the contact angle implied that this polymer was surprisingly hydrophobic (87.4 ).Material 7. When PP5 and PP6 were cured, the resulting polymers were brittle due to the high-cross-linking density which is due to each repeat unit containing a site

28、for radicalcross-linking. We hope to further increase the flexibility of itaconate-based polyesters by producing a copolymer in an attempt to dilute the cross-linking sites. In order to accom-plish this goal, AA was included in the monomer feed; DMI: AA:MPD = 1:3:4. The synthesis was identical to th

29、e proce-dure used for PP5 and PP6. The inclusion of AA caused a large increase in the molecular weight of the prepolymer, which obtained ÆMn æ = 11 900 g/mol (Table 2). TheTG of PP7, -57.6 C, was again low due to the choice of the diol. The branched structure of MPD prevented efficient pac

30、king, which resulted in a low T gPolymer 7 displayed a YM, UTS , and RS of approximately 2 MPa, 2 MPa, and 100%, respectively ( Table 3) . The hydrated state of this poly-ester produces similar mechanical characteristics; the new values are 2 .4 MPa ( YM) , 1.9 MPa ( U TS) , and 100% ( R S) Polyeste

31、r 7 is the most hydrophobic material t hat w asdesign ed fo r t hi s study. Three factor s l ed to this result:( i ) P P7 was linear; ( i i) the d iol used i n the polymerization, MPD, was hydrophobic; ( iii) a significant portion of AA w asemployed as a comonomer. As stated previously, AA contains

32、a longer hydrocarbon segment t ha n I A . Because of this hydrophobic nature, the water swelling value was low ( 1.6%) while t h e contact angle measurement was high ( 9 6.0 )(Figure2and T a b l e 3 ) . Finally , t he soluble fr action o f this thermoset was similar to t ha t o f the three homopolym

33、ers studied h ere ( 5.6%) .各種對比 親水性 疏水性 文獻(xiàn)閱讀 記憶彈性體作者Oliver Goerz and Helmut Ritter題目Polymers with shape memory effect from renewable resources: crosslinking of polyestersbased on isosorbide, itaconic acid and succinic acid 期刊 Polym Int 2013;62: 709 712摘要Polycondensation of isosorbide with itaconic a

34、cid and succinic acid was performed in the presence of sulfuric acid as a catalyst in toluene around 140C under microwave irradiation. Molar ratios of itaconic acid were varied to investigate the influence of itaconic acid o n molecular weights and glass transition temperatures. For polyesters of is

35、osorbide, itaconic acid and succinic acid Tg values were found from 57C to 65C. The molecular weights obtained varied from 1200 Da for poly(isosorbide itaconate)UPE100 up to 3500 Da for p oly(isosorbide succinate) UPE0. The copolyesters obtained were crosslinked radically with dimethyl itaconate giv

36、ing a round shaped material with slightly raised T g values up to 74C. Furthermore, with dimethyl itaconate crosslinked copolyesters showed a one-way shape memory effect upon h eating after deformation at the glass transition temperature.阻聚劑采用的是 phenothiazin 硫代二苯胺 Synthesis of poly(isosorbide itacon

37、ate) ( UPE100) A 100 mL long-necked round bottom flask was charged with isosorbide (5.58 g, 40 mmol), itaconic acid (5.20 g, 40 mmol), sulfuric acid (0.02 g, 0.2 mmol), phenothiazin (0.02 g, 0.1 mmol)and 80 mL of toluene. The flask was fitted with a Dean Stark apparatus and the mixture was reacted u

38、nder microwave irradiation at 140C with a power consumption of 200 300 Wfor 4 h. The solvent was removed and the crude product was diluted in 30 mL of dichloromethane and precipitated in 300 mL methanol. The precipitated product was isolated by decantation and dried under vacuumSynthesis of poly(iso

39、sorbide itaconate-co -succinate) ( UPE90, UPE50, UPE10)Synthesis of poly(isosorbide succinate) ( UPE0) A 100 mL long-necked round bottom flask was charged with isosorbide (5.58 g, 40 mmol), succinic acid (4.72 g, 40 mmol), sulfuric acid (0.02 g, 0.2 mmol) and 80 mL of toluene. The flaskwas fitted wi

40、th a Dean Stark apparatus and the mixture was reacted under microwave irradiation at 140C with a power consumption of 200 300 W for 4 h. The solvent was removed and the crude product was diluted in 30 mL of dichloromethane and precipitated in 300 mL methanol. The precipitated product was isolated by

41、 decantation and dried under vacuum.Crosslinking o f p olyesters UPE100, UPE90, UPE50 and UPE10 with dimethyl itaconate Unsaturated polyester (0.47 g) was added to a 25 mL round bottom flask and dissolved in dimethyl itaconate (2.37 g, 15 mmol). The reaction mixture was flushed with N2 for 15 min. T

42、hen V65 (0.014 g, 0.06 mmol) was added and the mixture was transferred into a mold and heated to 60C for 72 h. The resulting crosslinked polyester was removed from the mold and hardened at 70C for an additional 48 hRESULTS AND DISCUSSION The unsaturated polyester UPE100 was synthesized from isosor-b

43、ide and itaconic acid which were polycondensed in the presence of a catalytic amount of sulfuric acid. Water was removed by azeotropic distillation in toluene. thermal conditions at 140Cfor 48 h which led to low yields below 10% and low Mw valuesbetween 500 and 800 Da. microwave irradiation a more c

44、onsistent heating of the reaction mixture was achieved andthe reaction time could be shortened to 4 h. Furthermore the yield could be slightly increased up to 17% and GPC measurements showed Mw values of 1200 Da. 這里討論到分子量的問題 催化劑或者溫度 都變化不大，因?yàn)楫惿嚼娲嫉奶厥饨Y(jié)構(gòu) 很難做高分子量 和產(chǎn)率 These values should be considered car

45、efully because GPC measurements which are calibrated with polystyrene standards tend to overestimateMw values of aliphatic polyesters. This means that the real values will be much lower than the ones obtained. However, higher values could not beobtained even by increasing the duration of the reactio

46、n, the temperature or the amount of catalyst. This can be explained as due to the sterically demanding structure of isosorbide as well as itaconic acid and the slow reaction rate of secondary alcohols during esterification. We also discovered that UPE100 precipitated during the reaction, which can b

47、e caused by lack of solubility in toluene. A possible polymerization of the double bond could be excluded. Earlier reported reactions of isosorbide with unsaturated diacids in toluene show similar low Mw values.The aim of this reaction series with the use of succinic acid as a further biobased diaci

48、d was to achieve an improvement of molecular weights to higher values. In addition, the influence of incorporated succinic acid on glass transition temperatures was also investigated衣康酸比較丁二酸與異山梨醇的活性小很多 空間位阻之類的原因 The replacement of itaconic acid with succinic acid led to higher molecular weights (350

49、0 Da for UPE0) and yields increased from 17% to 68% with the incorporation of succinic acid. It can be assumed that itaconic acid is less reactive than succinic in polycondensation with isosorbide because of the steric hindrance and electronic difference. The polyesters obtained were completely amor

50、phous with T g values from 57Cto65C without any continuity.We had to conclude, contrary to our expectations, that the disk shaped materials UPE100, UPE90 and UPE50 showed a shape memory effect. The disks were slightly deformed at T g without breaking up and were cooled to room temperature. The disks

51、 kept their curved shape after cooling and formed back to the original shape after reheating to T g .The result is shown in Fig.2Bio based Poly(propylene sebacate) as Shape Memory Polymer with Tunable Switching Temperature for Potential Biomedical ApplicationsBiomacromolecules 2011, 12, 13121321ABST

52、RACT: From the point of better biocompatibility and sustainability, biobased shape memory polymers (SMPs) are highly desired. We used 1,3-propanediol, sebacic acid, and itaconic acid, which have been industrially produced via fermentation or extraction with large quantities as the main raw materials

53、 for the synthesis of biobased poly(propylene sebacate). Diethylene glycol was used to tailor the exibility of the polyester. The resulted polyesters were found to be promising SMPs with excellent shape recovery and xity (near 100% and independent of thermomechanical cycles). The switching temperatu

54、re and recovery speed of the SMPs are tunable by controlling the composition of the polyesters and their curing extent. The continuously changed switching temperature ranging from 12 to 54 C was realized. Such temperature range is typical for biomedical applications in the human body. The molecular

55、and crystalline structures were explored to correlate to the shape memory behavior. The combination of potential biocompatibility and biodegradability of the biobased SMPs makes them suitable for fabricating biomedical devices.簡介 固定部分 臨時(shí)部分 Shape memory polymers (SMPs) have a sensitive response to th

56、e external stimuli, such as temperature, pH, humidity , light, electricity, and so o n. Until now, the majority of the reported SMPs are stimulated by tempera ture. All SMPs contain two networks ,which are call ed the permanent networks and the temporary networks. The perm anent networks are either

57、covalent cross-links or physical cross-links, and the “ bonds” exist above transition temperature ( T trans). The temporary networks typically rely upon vitrification,crystallization,or some other physical interact ion such as hydrogen bonding and ionic bonding. 6SMPshave a permanent shape t hat i s

58、 provided b y a permanent network,but they can be deformed above T trans. Temporary network isfixed into a temporary shape when the SMP is cool ed under stress to below T trans. W hen reheated above T trans without stress, the material assumes its permanent shape.生物基的好處 bio-based polyesters (BPEs )

59、生物基聚酯 Be cause of the structural characteristics of biobased polymers, their biocompatibility and exp ected biodegradability make them specially suitable for biomedical applications. Mean while, theenergy, re sources, and serious environment al problems influence our life deeply today. The full use of renewable resources and reducing dependence