Hyperbranched Polymers Based on Aliphatic Polyesters – Synthesis and Characterization
Само за регистроване кориснике
2008
Књига (Објављена верзија)
Метаподаци
Приказ свих података о документуАпстракт
Two series of hydroxy-functional hyperbranched polymers based on aliphatic polyesters have
been prepared from the 2,2-bis(hydroxymethyl)propionic acid (AB2 monomer) and the ditrimethylolpropane
(B4 functional core). A pseudo-one-step procedure was used for the
synthesis of seven different pseudo generation hyperbranched polyesters of the first series
(second, third, fourth, fifth, sixth, eight and tenth pseudo generation), while samples of the
second series (fourth, sixth and eight pseudo generation) were prepared by a one-step
procedure. The term “pseudo generation” refers to the presence of certain amount of the linear
repeating units in the structure of hyperbranched polymers. The structure and properties of the
self-synthesized hyperbranched polyesters, investigated with different characterization
techniques, were compared between each other, as well as with commercially available
hyperbranched polyesters of the similar structure and sample obtained by modification of the...
end –OH groups with stearic acid. Beside that, several investigated hyperbranched polyesters
were fractionated and a characterization of the obtained fractions was performed in order to
get more information about the structure of these polymers.
The experimental results obtained by NMR spectroscopy indicate that during the
synthesis of these hyperbranched polymers, –OH groups belonging to the terminal units had
bigger reactivity than linear ones. As a consequence of that, the degree of branching for all
investigated samples is lower than 0.50. The existence of side reaction products has been
proved qualitatively and quantitatively by NMR, acid number titration, MALDI-TOF and ESI
MS measurements. The side reaction which occurred to a highest amount during the synthesis
is the formation of the poly(bis-MPA). The degree of conversion of –COOH groups decreases
with increasing theoretical number of pseudo generation. The formation of cyclic structures
through intramolecular etherification and/or esterification is another side reaction which
occurred during the synthesis of polymers investigated in this work. The extent of cyclization
through the ester and ether bonds increased with increasing degree of polymerization. The
experimental results have also shown that up to the fifth pseudo generation (or sixth in the
case of the samples of series II) cyclization occurred through ester and ether bonds, while for
the higher generation samples cycles were formed as a consequence of the intramolecular
esterification. The results obtained in this work, as well as by other authors have shown that
for the commercial samples the extent of the side reactions occurred to a higher degree than
for the samples synthesized in this work. NMR, VPO and GPC measurements indicate that
the main consequences of the side reactions are: a) molar mass increases only up to the sixth
pseudo generation, b) determined values of the number average molar mass are significantly
lower than theoretical ones and c) distribution of the molar masses and sizes of all samples is
broad.
The best solvents for the polymers synthesized in this work and commercial
hyperbranched polyesters are 0.7 mass % solution of LiCl in DMAc and NMP. The limiting
viscosity number and the hydrodynamic radius of these samples increase up to the sixth
pseudo generation in these two solvents. The exponents obtained from the scaling relations of
the limiting viscosity number and hydrodynamic radii with molar mass for the samples of the
first series and commercial polymers all had values less than 0.5.
According to the data obtained by rheological technique, these polymers have a high
ability for the aggregation in the solution and in melt due to the presence of numerous –OH
groups. In solution, this ability decreased with increasing theoretical number of pseudo
generation, with decreasing concentration and with increasing temperature of the solution.
Therefore, at temperatures lower than 50 oC solutions which concentration is higher than 45
mass % show shear-thinning behaviour in NMP. On the other side, lower concentrated solutions of all investigated hyperbranched polymers act as non-entangled Newtonian liquids.
Newtonian behaviour is also observed at higher temperatures (T > 70 oC) in melt for the
polyesters from fourth till sixth pseudo generation.
The thermal stability of investigated hyperbranched polyesters, determined by
thermogravimetry, increases with increasing number of the pseudo generation. Using the
Ozawa-Flynn-Wall method the activation energy of thermal degradation of these samples was
determined.
A comparison between the hyperbranched polyesters synthesized by pseudo-one-step
and one-step procedure reveals that their properties are different from each other. It was
generally concluded that polymers of the second series have somewhat lower values of degree
of branching, i.e. higher portion of the linear units, higher extent of side reactions, broader
molar mass distribution, higher values of the limiting viscosity number, higher values of
complex viscosity in melt and poorer thermal stability than samples synthesized by pseudoone-
step procedure.
The marked influence of the nature of the terminal groups on the rheological and
thermal properties has been detected. By modification of the end –OH groups with stearic
acid thermal stability has been improved. On the other side, the presence of the long alkyl
chain ends, instead of the polar –OH groups, has reduced the possibility for the H-bonding
and value of the glass transition temperature.
Кључне речи:
Hydroxy-functional hyperbranched polymers / NMR spectroscopy / MALDI-TOF MS / ESI MS / Vapour pressure osmometry / Gel permeation chromatography / Viscosimetry of the diluted solutions / Rheology / ThermogravimetryИзвор:
2008Издавач:
- Saarbrücken, Deutschland : VDM Verlag Dr. Müller Aktiengesellschaft & Co. KG
Институција/група
IHTMTY - BOOK AU - Vuković, Jasna PY - 2008 UR - https://cer.ihtm.bg.ac.rs/handle/123456789/6894 AB - Two series of hydroxy-functional hyperbranched polymers based on aliphatic polyesters have been prepared from the 2,2-bis(hydroxymethyl)propionic acid (AB2 monomer) and the ditrimethylolpropane (B4 functional core). A pseudo-one-step procedure was used for the synthesis of seven different pseudo generation hyperbranched polyesters of the first series (second, third, fourth, fifth, sixth, eight and tenth pseudo generation), while samples of the second series (fourth, sixth and eight pseudo generation) were prepared by a one-step procedure. The term “pseudo generation” refers to the presence of certain amount of the linear repeating units in the structure of hyperbranched polymers. The structure and properties of the self-synthesized hyperbranched polyesters, investigated with different characterization techniques, were compared between each other, as well as with commercially available hyperbranched polyesters of the similar structure and sample obtained by modification of the end –OH groups with stearic acid. Beside that, several investigated hyperbranched polyesters were fractionated and a characterization of the obtained fractions was performed in order to get more information about the structure of these polymers. The experimental results obtained by NMR spectroscopy indicate that during the synthesis of these hyperbranched polymers, –OH groups belonging to the terminal units had bigger reactivity than linear ones. As a consequence of that, the degree of branching for all investigated samples is lower than 0.50. The existence of side reaction products has been proved qualitatively and quantitatively by NMR, acid number titration, MALDI-TOF and ESI MS measurements. The side reaction which occurred to a highest amount during the synthesis is the formation of the poly(bis-MPA). The degree of conversion of –COOH groups decreases with increasing theoretical number of pseudo generation. The formation of cyclic structures through intramolecular etherification and/or esterification is another side reaction which occurred during the synthesis of polymers investigated in this work. The extent of cyclization through the ester and ether bonds increased with increasing degree of polymerization. The experimental results have also shown that up to the fifth pseudo generation (or sixth in the case of the samples of series II) cyclization occurred through ester and ether bonds, while for the higher generation samples cycles were formed as a consequence of the intramolecular esterification. The results obtained in this work, as well as by other authors have shown that for the commercial samples the extent of the side reactions occurred to a higher degree than for the samples synthesized in this work. NMR, VPO and GPC measurements indicate that the main consequences of the side reactions are: a) molar mass increases only up to the sixth pseudo generation, b) determined values of the number average molar mass are significantly lower than theoretical ones and c) distribution of the molar masses and sizes of all samples is broad. The best solvents for the polymers synthesized in this work and commercial hyperbranched polyesters are 0.7 mass % solution of LiCl in DMAc and NMP. The limiting viscosity number and the hydrodynamic radius of these samples increase up to the sixth pseudo generation in these two solvents. The exponents obtained from the scaling relations of the limiting viscosity number and hydrodynamic radii with molar mass for the samples of the first series and commercial polymers all had values less than 0.5. According to the data obtained by rheological technique, these polymers have a high ability for the aggregation in the solution and in melt due to the presence of numerous –OH groups. In solution, this ability decreased with increasing theoretical number of pseudo generation, with decreasing concentration and with increasing temperature of the solution. Therefore, at temperatures lower than 50 oC solutions which concentration is higher than 45 mass % show shear-thinning behaviour in NMP. On the other side, lower concentrated solutions of all investigated hyperbranched polymers act as non-entangled Newtonian liquids. Newtonian behaviour is also observed at higher temperatures (T > 70 oC) in melt for the polyesters from fourth till sixth pseudo generation. The thermal stability of investigated hyperbranched polyesters, determined by thermogravimetry, increases with increasing number of the pseudo generation. Using the Ozawa-Flynn-Wall method the activation energy of thermal degradation of these samples was determined. A comparison between the hyperbranched polyesters synthesized by pseudo-one-step and one-step procedure reveals that their properties are different from each other. It was generally concluded that polymers of the second series have somewhat lower values of degree of branching, i.e. higher portion of the linear units, higher extent of side reactions, broader molar mass distribution, higher values of the limiting viscosity number, higher values of complex viscosity in melt and poorer thermal stability than samples synthesized by pseudoone- step procedure. The marked influence of the nature of the terminal groups on the rheological and thermal properties has been detected. By modification of the end –OH groups with stearic acid thermal stability has been improved. On the other side, the presence of the long alkyl chain ends, instead of the polar –OH groups, has reduced the possibility for the H-bonding and value of the glass transition temperature. PB - Saarbrücken, Deutschland : VDM Verlag Dr. Müller Aktiengesellschaft & Co. KG T1 - Hyperbranched Polymers Based on Aliphatic Polyesters – Synthesis and Characterization UR - https://hdl.handle.net/21.15107/rcub_cer_6894 ER -
@book{ author = "Vuković, Jasna", year = "2008", abstract = "Two series of hydroxy-functional hyperbranched polymers based on aliphatic polyesters have been prepared from the 2,2-bis(hydroxymethyl)propionic acid (AB2 monomer) and the ditrimethylolpropane (B4 functional core). A pseudo-one-step procedure was used for the synthesis of seven different pseudo generation hyperbranched polyesters of the first series (second, third, fourth, fifth, sixth, eight and tenth pseudo generation), while samples of the second series (fourth, sixth and eight pseudo generation) were prepared by a one-step procedure. The term “pseudo generation” refers to the presence of certain amount of the linear repeating units in the structure of hyperbranched polymers. The structure and properties of the self-synthesized hyperbranched polyesters, investigated with different characterization techniques, were compared between each other, as well as with commercially available hyperbranched polyesters of the similar structure and sample obtained by modification of the end –OH groups with stearic acid. Beside that, several investigated hyperbranched polyesters were fractionated and a characterization of the obtained fractions was performed in order to get more information about the structure of these polymers. The experimental results obtained by NMR spectroscopy indicate that during the synthesis of these hyperbranched polymers, –OH groups belonging to the terminal units had bigger reactivity than linear ones. As a consequence of that, the degree of branching for all investigated samples is lower than 0.50. The existence of side reaction products has been proved qualitatively and quantitatively by NMR, acid number titration, MALDI-TOF and ESI MS measurements. The side reaction which occurred to a highest amount during the synthesis is the formation of the poly(bis-MPA). The degree of conversion of –COOH groups decreases with increasing theoretical number of pseudo generation. The formation of cyclic structures through intramolecular etherification and/or esterification is another side reaction which occurred during the synthesis of polymers investigated in this work. The extent of cyclization through the ester and ether bonds increased with increasing degree of polymerization. The experimental results have also shown that up to the fifth pseudo generation (or sixth in the case of the samples of series II) cyclization occurred through ester and ether bonds, while for the higher generation samples cycles were formed as a consequence of the intramolecular esterification. The results obtained in this work, as well as by other authors have shown that for the commercial samples the extent of the side reactions occurred to a higher degree than for the samples synthesized in this work. NMR, VPO and GPC measurements indicate that the main consequences of the side reactions are: a) molar mass increases only up to the sixth pseudo generation, b) determined values of the number average molar mass are significantly lower than theoretical ones and c) distribution of the molar masses and sizes of all samples is broad. The best solvents for the polymers synthesized in this work and commercial hyperbranched polyesters are 0.7 mass % solution of LiCl in DMAc and NMP. The limiting viscosity number and the hydrodynamic radius of these samples increase up to the sixth pseudo generation in these two solvents. The exponents obtained from the scaling relations of the limiting viscosity number and hydrodynamic radii with molar mass for the samples of the first series and commercial polymers all had values less than 0.5. According to the data obtained by rheological technique, these polymers have a high ability for the aggregation in the solution and in melt due to the presence of numerous –OH groups. In solution, this ability decreased with increasing theoretical number of pseudo generation, with decreasing concentration and with increasing temperature of the solution. Therefore, at temperatures lower than 50 oC solutions which concentration is higher than 45 mass % show shear-thinning behaviour in NMP. On the other side, lower concentrated solutions of all investigated hyperbranched polymers act as non-entangled Newtonian liquids. Newtonian behaviour is also observed at higher temperatures (T > 70 oC) in melt for the polyesters from fourth till sixth pseudo generation. The thermal stability of investigated hyperbranched polyesters, determined by thermogravimetry, increases with increasing number of the pseudo generation. Using the Ozawa-Flynn-Wall method the activation energy of thermal degradation of these samples was determined. A comparison between the hyperbranched polyesters synthesized by pseudo-one-step and one-step procedure reveals that their properties are different from each other. It was generally concluded that polymers of the second series have somewhat lower values of degree of branching, i.e. higher portion of the linear units, higher extent of side reactions, broader molar mass distribution, higher values of the limiting viscosity number, higher values of complex viscosity in melt and poorer thermal stability than samples synthesized by pseudoone- step procedure. The marked influence of the nature of the terminal groups on the rheological and thermal properties has been detected. By modification of the end –OH groups with stearic acid thermal stability has been improved. On the other side, the presence of the long alkyl chain ends, instead of the polar –OH groups, has reduced the possibility for the H-bonding and value of the glass transition temperature.", publisher = "Saarbrücken, Deutschland : VDM Verlag Dr. Müller Aktiengesellschaft & Co. KG", title = "Hyperbranched Polymers Based on Aliphatic Polyesters – Synthesis and Characterization", url = "https://hdl.handle.net/21.15107/rcub_cer_6894" }
Vuković, J.. (2008). Hyperbranched Polymers Based on Aliphatic Polyesters – Synthesis and Characterization. Saarbrücken, Deutschland : VDM Verlag Dr. Müller Aktiengesellschaft & Co. KG.. https://hdl.handle.net/21.15107/rcub_cer_6894
Vuković J. Hyperbranched Polymers Based on Aliphatic Polyesters – Synthesis and Characterization. 2008;. https://hdl.handle.net/21.15107/rcub_cer_6894 .
Vuković, Jasna, "Hyperbranched Polymers Based on Aliphatic Polyesters – Synthesis and Characterization" (2008), https://hdl.handle.net/21.15107/rcub_cer_6894 .