High-Resolution <sup>13</sup>C and <sup>1</sup>H Solution NMR Study of Poly(lactide)

Thakur, Khalid A. M.; Kean, Robert T.; Hall, Eric S.; Kolstad, Jeffrey J.; Lindgren, Tim A.; Doscotch, Matthew A.; Siepmann, J. Ilja; Munson, Eric J.

doi:10.1021/ma9615967

Cited by 248 publications

(205 citation statements)

References 17 publications

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“…Os sinais encontrados no 1 H RMN para o copolímero poli(L-co-D,L ácido lático) estão de acordo tanto com o reportado pela literatura [19] Pode-se verificar claramente que existem mais desdobramentos nos sinais referentes ao copolímero comparado aos verificados no homopolímero. Esses desdobramentos de sinais originam-se da estereosensitividade devido à presença de dois pares enantioméricos do acido láctico no copolímero, que são diastereoisomericamente diferentes, ou seja, pares LL/DD e os LD/DL [20] a Figura 3, compara o copolímero PLDLA-3 com o comercial (Purac).…”

Section: Resultsunclassified

Síntese e caracterização do copolímero poli (L-co-D,L Ácido Láctico)

Motta

Duek²

2007

Polímeros

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Resumo: A aplicação de polímeros biorreabsorvíveis em próteses temporárias é constante nos procedimentos médicos relacionados a fraturas ósseas. Dentre os polímeros bioreabsorvíveis, o poli(L-co-D, L ácido láctico), PLDLA, na relação 70:30, tem sido estudado visando à obtenção de placas e parafusos para a recuperação de traumas nas regiões buco e crânio-maxilofacial. Nessa relação de monômeros obtém-se um polímero amorfo, o que permite uma adaptação do dispositivo ao local do implante durante a cirurgia. Um fator limitante para o uso desse polímero é seu alto custo em função da importação. Neste trabalho o PLDLA foi sintetizado através da polimerização em massa dos monômeros cíclicos do L-ácido láctico e do D, L ácido láctico, utilizando como catalisador o Sn(Oct) 2 . Obteve-se material de alta massa molar (Mw = 10 5 g/mol), o qual foi caracterizado por 1 H RMN, 13 C RMN, GPC, FTIR e DSC. Palavras-chave: Poli(L-co-D,L ácido lático), síntese, caracterização. Synthesis and Characterization of the Copolymer Poly(L-co-D,L lactic acid)Abstract: Bioreabsorbable polymers are routinely used as temporary prostheses for fractured bones. Among the bioreabsorbable polymers the poly(L-co-D, L lactic acid), PLDLA, in the 70:30 rate has been studied to obtain plates and screws to recuperate traumas in the cranium and maxilla facial regions. In this monomers rate, an amorphous polymer is obtained, which allows adaptation of devices in the local for the implant during the surgery. A limiting factor to use this polymer is its high cost, due to the importation process. In this work PLDLA was synthesized by mass polymerization of the cyclical monomers L-lactic acid and D, L lactic acid, using Sn(Oct) 2 as catalyst. A material with high molar mass (10 5 g/mol) was obtained and characterized by 1 H RMN, 13 C RMN, GPC, FTIR and DSC. Keywords: Poly(L-co-D,L lactic acid), synthesis, characterization. IntroduçãoDispositivos obtidos a partir de polímeros biorreabsorvíveis aplicados em osteofixação ao têm sido cada vez mais aceitos na área de ortopedia e traumatologia [1] . Atualmente, dispositivos como mini placas e parafusos desses polímeros são usados rotineiramente na região crânio e bucomaxilofacial, substituindo os dispositivos metálicos [2] .A utilização de materiais permanentes, como o titânio, na fixação de fraturas já data de muitas décadas. Apesar da elevada propriedade mecânica que tais implantes apresentam, o grande inconveniente de sua utilização reside nos elevados percentuais de remoção destes dispositivos do organismo, após a consolidação da fratura. Um exemplo que descreve a necessidade de remoção dos implantes metálicos no organismo pode ser dado quando o implante é aplicado a fraturas na região craniofacial em crianças, tendo em vista que a não-remoção do mesmo, implica num comprometimento do crescimento ósseo destes indivíduos, além da possibilidade de migração destes implantes [2][3][4][5][6][7] . Pesquisa recente [8] mostrou que para a maioria dos pacientes, 91%, que possuem algum tipo de implante metálico, o aspecto...

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Section: Resultsunclassified

Síntese e caracterização do copolímero poli (L-co-D,L Ácido Láctico)

Motta

Duek²

2007

Polímeros

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“…At 150 °C, the multiblock index increased with time and reached 2.27 at 65 h. At 180 °C, the multiblock index was 2.78 at 25 h and reached 2.93 after 65 h. Figure 4 shows the methyl protons decoupled from the methine protons of the PLA-PEG multiblock copolymers. The spectral signals were assigned according to previous studies [20][21][22][23]. The subscripts i and s indicate isotactic and syndiotactic, respectively.…”

Section: Synthesis Of Multiblock Copolymersmentioning

confidence: 99%

Size-Controlled Nanomicelles of Poly(lactic acid)–Poly(ethylene glycol) Copolymers with a Multiblock Configuration

et al. 2015

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Abstract:The ability to control the micelle size of poly(lactic acid) and poly(ethylene glycol) (PLA-PEG) block copolymers is important for controlling their circulation in blood cell recognition, drug release and therapeutic effects. We successfully controlled the micelle size by changing the block number of copolymers (multiblock index). PLA-PEG multiblock copolymers with multiblock indexes ranging from 1.35 to 2.78 were synthesized by direct polycondensation with tin chloride/p-toluenesulfonic acid binary catalysts, using PEG with a molecular weight (Mw) of 3200 Da. The Mw of PLA-PEG copolymers increased with an increase in the multiblock index, while micelle size, measured by dynamic light scattering, decreased greatly from 349 to 28 nm. In addition, the X-ray diffraction peak of the PLA crystal disappeared when the multiblock index was increased. These results indicate that a multiblock structure is useful for controlling micelle size without changing the PLA/PEG composition or PEG molecular weight, which strongly influences other micelle features.

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“…Figure 2 compares the 1 H-NMR spectra of the copolymer PLDLA and the terpolymer PLDLA-TMC. In the copolymer spectrum, a multiplet at 5.12-5.24 ppm was assigned to the CH proton (b), while the quartet at 1.55-1.59 ppm was assigned to the CH 3 protons (a) [34] . In the case of PLDLA-TMC, the triplet at 2.05 ppm was assigned to the CH 2 protons (c), while the triplet at 4.24 ppm was assigned to OCH 2 …”

Section: Proton Nuclear Magnetic Resonance ( 1 H-nmr)mentioning

confidence: 99%

Synthesis and characterization of a novel terpolymer based on L-lactide, D,L-lactide and trimethylene carbonate

Motta

Duek

2014

Mat. Res.

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Terpolymers of L-lactide, D,L-lactide and trimethylene carbonate (TMC) were synthesized via the ring-opening polymerization reaction for cyclic monomers using stannous octoate as the initiator at a ratio of ~0.05 mol% (monomers/(SnOct) 2 ). Synthesis was done at 130 °C for 48 h. The inclusion of TMC, an aliphatic elastomeric polycarbonate, alongside polymer chain segments containing L-lactide and D,L-lactide, was expected to yield a material with improved properties such as increased elongation; this would overcome the limitation of copolymers consisting entirely of lactide and D,L-lactide. The terpolymer properties were assessed by Nuclear magnetic resonance spectroscopy 1 H and 13 C NMR, infrared spectroscopy, differential scanning calorimetry and thermogravimetry, with particular attention being given to the effect of TMC on the copolymer of L-lactide-co-D,L-lactide. The mixing of these polymers resulted in material with a high molar mass (10 5 g/mol). The mechanical properties of the terpolymer were assessed using pins of this material that were tested by mechanical flexion at three points. When compared with results for the copolymer PLDLA there was a decrease in Young's modulus for the TMC-containing terpolymer.

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High-Resolution ¹³C and ¹H Solution NMR Study of Poly(lactide)

Cited by 248 publications

References 17 publications

Síntese e caracterização do copolímero poli (L-co-D,L Ácido Láctico)

Síntese e caracterização do copolímero poli (L-co-D,L Ácido Láctico)

Size-Controlled Nanomicelles of Poly(lactic acid)–Poly(ethylene glycol) Copolymers with a Multiblock Configuration

Synthesis and characterization of a novel terpolymer based on L-lactide, D,L-lactide and trimethylene carbonate

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High-Resolution 13C and 1H Solution NMR Study of Poly(lactide)

Cited by 248 publications

References 17 publications

Síntese e caracterização do copolímero poli (L-co-D,L Ácido Láctico)

Síntese e caracterização do copolímero poli (L-co-D,L Ácido Láctico)

Size-Controlled Nanomicelles of Poly(lactic acid)–Poly(ethylene glycol) Copolymers with a Multiblock Configuration

Synthesis and characterization of a novel terpolymer based on L-lactide, D,L-lactide and trimethylene carbonate

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High-Resolution ¹³C and ¹H Solution NMR Study of Poly(lactide)