Técnicas de Caracterização de Polímeros

Terra, Idelma A. A.; Aoki, Pedro H.B.; Delezuk, Jorge Augusto de Moura; Martins, Maria Alice; Manrich, Anny; Silva, Maycon Jhony; Costa, Mardoqueu Martins da; Torres, Bruno Bassi Millan; Avansi, Waldir; Ferreira, Claudia Santana Gonçalves; Sousa, Marcos da Silva; Volpati, Diogo; Miranda, Paulo B.

doi:10.5151/9786555502527-15

Cited by 8 publications

(39 citation statements)

References 6 publications

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“…The curves obtained through DSC show that the separately electrospun polymers only presented a glass transition temperature (T g ), which defines them as completely amorphous polymers. Therefore, PLDLA presented T g at 56 C, a value close to that reported by Motta and Duek (58 C), 30 whereas NR exhibited a T g of À65 C, corroborating the results of Guerra et al 39 An apparent endothermic transition was also observed at the end of the T g of NR, which, according to Canevarolo Jr., 52 is attributed to the greater relaxation and flexibility of the elastomeric chains. Similarly, the sample referring to PLDLA +1.5% NR presented a single T g at 45 C, indicating a possible interaction between the electrospun polymer chains at this proportion.…”

Section: Differential Scanning Calorimetrysupporting

confidence: 86%

Development of co‐electrospun membrane composed poly(l‐co‐d,l‐lactic acid) and natural rubber with potential application in dermal dressing

Pinto,

V. Quevedo,

Komatsu

et al. 2024

J of Applied Polymer Sci

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Wound healing represents a global challenge for the healthcare system, resulting in substantial costs and physical and emotional impacts on individuals. There is an increasing demand for innovative alternatives to treat this condition. The co‐electrospinning technique enables the production of porous membrane composed of natural and synthetic polymers, which exhibit unique functions and adjustable mechanical properties that assist in the tissue healing process. Therefore, the present study aims to investigate the physical–chemical, mechanical, and biological properties of membrane composed of poly(l‐co‐d,l‐lactic acid) (PLDLA) co‐electrospun with different concentrations of natural rubber (NR) (1.5%, 2.0%, and 2.5%). Scanning electron microscopy analysis revealed the porous surface of the membranes. Fourier‐transform infrared spectroscopy confirmed the presence of NR in the material. The low Young's modulus obtained in the mechanical tensile test for the PLDLA membrane co‐electrospun with 1.5% NR indicated its elastic capacity under low tension. The results corroborate with the differential scanning calorimetry, and thermogravimetric analysis, which highlights the compatibility between polymers at this specific proportion, as well as in vitro biocompatibility. The findings underscore the potential of PLDLA and NR co‐electrospun membranes as promising candidates for formulating biomaterials for applications such as dermal dressings.

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Section: Differential Scanning Calorimetrysupporting

confidence: 86%

Development of co‐electrospun membrane composed poly(l‐co‐d,l‐lactic acid) and natural rubber with potential application in dermal dressing

Pinto,

V. Quevedo,

Komatsu

et al. 2024

J of Applied Polymer Sci

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“…Following the first heating of the samples, it is usually applied high cooling rates in order to do not provide enough time for the material crystallization and, consequently the amorphous region of the polymer becomes higher, emphasizing the T g identification in the second heating curves. 20,25 Although it was set 50 C min À1 as cooling rate, the T g was detected only in the PHBV curve (1.4 C).…”

Section: Differential Scanning Calorimetrymentioning

confidence: 99%

“…In DMTA analysis, transition temperatures are easily determined by the curves behavior, 25,30 by the application of periodic load in a range of temperature, considering the viscoelastic properties of the materials. Figure 4 shows the DMTA curves of storage modulus (E 0 ), loss modulus (E 00 ) and tan δ for each sample composition.…”

Section: Dynamic Mechanical Thermal Analysismentioning

confidence: 99%

Effects of tributyrin as plasticizer in poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) on processability, mechanical, and thermal properties

Carvalho

Silva

Lemes

2023

J of Applied Polymer Sci

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The development of biodegradable polymers has been stimulated owing to the inappropriate litter disposing in order to replace conventional polymers with long‐time degradation. As their performance is a challenge to this replacement, the insertion of additives in biodegradable polymers such as poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) consists in an effective way of adjusting their properties. For this reason, it was analyzed the incorporation of tributyrin (TB) in the matrix of PHBV as a plasticizer, so that higher plastic deformation is achieved. Samples of neat PHBV and with plasticizer concentrations of 5, 10, and 15 wt% were prepared by double screw extruder followed by press molding under temperature. Plasticizer exudation test confirmed the presence of TB in the samples of PHBV. Mechanical test showed the highest value of tensile strength and elongation at break for PHBV/5TB, with 23.4 MPa and 2.84%, respectively. It was observed at differential scanning calorimetry and dynamic mechanical thermal analysis that the PHBV/5TB resulted in an increase of 3% on crystallinity, a decrease of 3% on melting temperature, and a decrease of 46% and 29% on glass transition temperature by E″ and tan δ curves, respectively, compared with neat PHBV. Thus, PHBV/5TB was determined as the most appropriate composition for enhancing processability and properties of PHBV.

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“…A cromatografia de permeação em gel (do inglês GPC, Gel Permeation Chromatography), também conhecida como cromatografia por exclusão de tamanho, é geralmente utilizada para determinar a massa molar e a distribuição de massa molar de polímeros. Baseia-se no princípio de fracionamento das cadeias de um polímero, o qual envolve a separação do polímero a ser analisado em um número muito grande de frações com diferentes massas molares [58,59].…”

Section: Cromatografia De Permeação Em Gelunclassified

“…Quando aquecidos em atmosfera inerte, estes podem sofrer cisão de cadeia, reticulação ou carbonização. [58].…”

Section: Análise Termogravimétricaunclassified

Reciclagem química de espumas de poliuretano

Ribeiro¹,

Paoli²

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Fevereiro de 2010ii v "O mundo é como um espelho que devolve a cada pessoa o reflexo de seus próprios pensamentos. A maneira como você encara a vida é que faz toda diferença." Luiz Fernando Veríssimo vii Dedico este trabalho aos meus pais, que me ensinaram a lutar pelos ideais com sabedoria, perseverança, honestidade e dignidade.Ao Aloizio Junior, pelo amor, dedicação e paciência nestes anos ao meu lado.A toda família, pelo apoio, pela motivação e pela compreensão. ix AGRADECIMENTOSAos meus pais Alexandre e Rosa, pelo carinho e pelos exemplos deixados.À minha família, cada um que, à sua maneira esteve ao meu lado, e me deu bastante apoio

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Técnicas de Caracterização de Polímeros

Cited by 8 publications

References 6 publications

Development of co‐electrospun membrane composed poly(l‐co‐d,l‐lactic acid) and natural rubber with potential application in dermal dressing

Development of co‐electrospun membrane composed poly(l‐co‐d,l‐lactic acid) and natural rubber with potential application in dermal dressing

Effects of tributyrin as plasticizer in poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) on processability, mechanical, and thermal properties

Reciclagem química de espumas de poliuretano

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