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Polymers from renewable resources — derivatives of tartaric and carbonic acids Karolina Tomczyk Abstract the PhD thesis entitled "Polymers from renewable resources — derivatives of tartaric and carbonic acids" the results of investigation on the preparation of new biodegradable polymers and modification of commercially available ones are presented.
The aim of the work was to modify polyesters and polyurethanes to increase their bio degradation rate, by increasing the hydrophilicity of such materials. An innovative solution was based on the use of tartaric acid derivatives as components in the synthesis of polyesters including polycarbonates , and polyurethanes.
In other method of hydrophilization biscyclic carbonates were reacted with diamines to obtain polyurethanes containing pendant hydroxyl groups. The first part of the thesis is a literature review, in which the use of renewable resources for production of chemicals and materials is described. This approach is one of the fundaments of a sustainable development of a society, requiring responsible management of material and energy resources.
Materials based on renewable resources are generally characterized by biocompatibility, and exhibit the ability to biodegrade without releasing toxic compounds to the environment. However, such biodegradable materials are still absent on our market, due to the lack of modern technologies of their production.
Therefore,development of new generation of materials, that are safe for human health, environmentally friendly, and biodegradable, is one of a major challenges for the polymer chemistry today. The second part concerns the possibility of the synthesis of L-tartaric acid derivatives protected by cyclic acetal: dimethyl ester of 4R,5R -2,2-dimethyl-1,3-dioxolan-4,5- dicarboxylic acid 2 and its reduced derivative 4S,5S -4,5-bis hydroxymethyl -2,2-dimethyl-1,3-dioxolane 3.
Synthesis of tartaric acid derivatives did not require complicated procedures for protecting the hydroxyl groups, as in the case of polymers based on other renewable material — glycerol, in which it is necessary to carry out the synthesis involving several stages, including selective protecting and deprotecting of hydroxyl groups, and palladium-catalyzed hydrogenation. Hydrophilic oligoesters were obtained from tartaric acid derivative 2 and diols containing from 3 to 12 carbon atoms in a molecule, tartaric acid derivative 3 and dimethyl succinate, as well as from both tartaric acid derivatives 2 and 3.
It was shown that resulting polymers undergo bio degradation very fast. Under these conditions deprotection of hydroxyl groups proceeds easily, significantly increases the hydrophilicity of the resultant polyesters.
In the third part of the thesis, the results of the polyesters synthesis, including aliphatic-aromatic poly ester-carbonates and methods of modification based on structural disturbances in regular structure of the polymer chain to increase the rate of bio degradation are presented. The advantage of aliphatic polyesters which are characterized by good biodegradability was combined with good mechanical and thermal properties of aromatic polyesters.
It was shown that larger number of different acidic or diol components in the polimer chain increases degradability of the copolymers. The most efficient method of the synthesis of aliphatic-aromatic copolyester is the use of previously obtained oligomers and cooligomers in transesterification reaction.
With the increase of terephthalate units incorporated, the rigidity of the polymer significantly increases, as well as its molecular weight. Therefore, the tensile strength and Young's modulus are also higher. Moreover, introduction of carbonate units into the polymer chain casues the decrease of glass transition temperature and melting point of the crystallites.
The fourth part of the work describes the studies on the preparation of aliphaticaromatic polyesters and poly ester-carbonates modified by tartaric acid derivatives. Tartaric acid ester derivative 2 was incorporated into the structure of aliphatic and aliphatic-aromatic polyesters, partially replacing the aliphatic dicarboxylic acid. Tartaric acid derivative — 4S,5S -4,5-bis hydroxymethyl -2,2-dimethyl-1,3-dioxolane 3 was introduced into polyesters, polycarbonates and polyurethanes, partially replacing 1,4-butanediol.
The developed method of the synthesis of aliphatic-aromatic copolyesters and poly ester-carbonates containing pendant hydrophilic hydroxyl groups allowed to significantly increase their rate of bio degradation.
Degradation was carried out in an buffer solution of different pH 7. It was proven that the modified polymers exhibit a much higher rate of bio degradation, compared to their analogues without a modifier. It was also observed that the rate of bio degradation of the copolymers can be controlled by the amount of incorporated tartaric acid derivative. It was also presented that significantly greater impact on hydrolytic degradation rate was observed when the hydrophilic acid component was introduced than that of hydrophilic diol.
Thermal and mechanical properties of the obtained copolymers were examined,revealing that the introduction of tartaric acid derivatives into the polymer chain, regardless of the type of the polymer, results in a slight deterioration of mechanical properties, both in tensile strength, and elongation at break. However, significantly increased bio degradation rate of these materials was their great advantage.
In the case of biodegradable polymers there is no strict requirements for good mechanical properties, since a key role is their ability to degrade. Such modified polyesters can be used in the packaging industry, as well as in medicine, as resorbable sutures or drug delivery carriers. The next chapter of the PhD thesis describes the synthesis of oligocarbonatediols based on simple derivatives of carbonic acid, such as dimethyl carbonate or cyclic carbonates, as well as diol derivative of tartaric acid [ 4S,5S -4,5-bis hydroxymethyl -2,2-dimethyl-1,3- dioxolane 3 ].
A two-stage method was developed for the synthesis of oligocarbonatediols from dimethyl carbonate, which allowed to obtain oligomers with planned molecular weights,without ether linkages in their structure, and with hydroxyl as the only end groups. The advantage of the oligocarbonatediols in comparison to polyetherols is their much higher resistance to oxidation, so they can be used to prepare polyurethanes of medical applications,including the production of an artificial heart.
Polyols of this type were used for the preparation of segmented polyurethanes. Oligocarbonatediols based on longer diols were reacted with cycloaliphatic isophorone diisocyanate to give hydrolysis resistant polyurethanes, which may be used as permanent implants. Oligocarbonatediols based on short diols including tartaric acid derivative 3 were reacted with a examethylene or tetramethylene diisocyanate, yielding hydrophilic polyurethanes, that can be used as shortterm implants.
After fulfilling its role, polyurethane can degrade to naturally occurring in the environment: putrescine and erythritol, and depending on the diol — 1,4-butanediol or 1,3-propanediol. Obtained poly carbonate-urethanes exhibited very good mechanical and thermal properties. Introducing tartaric acid derivative 3 caused significant hydrophilicity gain.
In addition, an increase of glass transition temperature, and melting point when compared to not modified analogues was observed. In the next part of the thesis, studies on the synthesis of new biscyclic carbonates derived from renewable resources such as carbohydrates were presented.
During the trial synthesis of biscyclic carbonates, it was observed that intramolecular etherification reaction occurs to five-membered cyclic carbonates after a certain time, leading to the formation of cyclic ethers. Therefore, I have examined the etherification process in terms of varying reaction time and substrate compounds having from 3 to 6 hydroxyl groups per molecule.
Moreover, developed method provides a new environmentally friendly approach to the synthesis of five-membered cyclic ether derivatives under non-acidic conditions. Obtained biscyclic carbonates have been used in the synthesis of hydrophilic polyurethanes containing pendant hydroxyl groups. This method is based on the reaction of biscyclic carbonates with diamines without a catalyst.
The reaction is carried out under mild conditions, and does not require protection of hydroxyl groups. An additional advantage of this method is no need to use toxic isocyanate for polyurethane synthesis. Karolina Tomczyk -. KarolinaTomczyk- praca doktorska. Powered by:. Tak Anuluj. Karolina Tomczyk Karolina Tomczyk -.
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Polymers from renewable resources — derivatives of tartaric and carbonic acids Karolina Tomczyk Abstract the PhD thesis entitled "Polymers from renewable resources — derivatives of tartaric and carbonic acids" the results of investigation on the preparation of new biodegradable polymers and modification of commercially available ones are presented. The aim of the work was to modify polyesters and polyurethanes to increase their bio degradation rate, by increasing the hydrophilicity of such materials. An innovative solution was based on the use of tartaric acid derivatives as components in the synthesis of polyesters including polycarbonates , and polyurethanes. In other method of hydrophilization biscyclic carbonates were reacted with diamines to obtain polyurethanes containing pendant hydroxyl groups. The first part of the thesis is a literature review, in which the use of renewable resources for production of chemicals and materials is described. This approach is one of the fundaments of a sustainable development of a society, requiring responsible management of material and energy resources. Materials based on renewable resources are generally characterized by biocompatibility, and exhibit the ability to biodegrade without releasing toxic compounds to the environment.
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