• JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
 
  Bookmark and Share
 
 
Doctoral Thesis
DOI
https://doi.org/10.11606/T.88.2004.tde-03092010-150253
Document
Author
Full name
Elisângela Corradini
Institute/School/College
Knowledge Area
Date of Defense
Published
São Carlos, 2004
Supervisor
Committee
Mattoso, Luiz Henrique Capparelli (President)
Curvelo, Antonio Aprigio da Silva
Maule, Agnieszka Joanna Pawlicka
Mei, Lucia Helena Innocentini
Souza, Ernesto Chaves Pereira de
Title in Portuguese
Desenvolvimento de blendas de zeína e amido de milho
Keywords in Portuguese
Amido
Biodegradação
Blendas poliméricas
Polímeros naturais
Propriedades mecânicas
Propriedades térmicas
Zeína
Abstract in Portuguese
O objetivo deste trabalho foi a produção de blendas a partir de zeína e amido de milho, procurando unir de forma otimizada as propriedades dos polímeros e suas características de processabilidade e o entendimento da correlação estrutura-propriedades destas blendas. Misturas de amidolzeína foram preparadas nas proporções de 0/100, 10190, 20180, 30170, 50150, 80120 e 10010 massa/massa%, utilizando glicerol como plastificante nas proporções de 22, 30 e 40% em relação a massa total dos polímeros. As formulações foram processadas em um misturador interno, tipo Haake, conectado ao reômetro de torque a 160°C. As misturas obtidas foram moldadas por compressão a 160°C. As propriedades das blendas foram aliadas por ensaios de absorção de umidade, difração de raios X, ensaios mecânicos (tração), calorimetria exploratória diferencial (DSC), termogravimetria (TG), análise termo dinâmica-mecânica, microscopia eletrônica de varredura (MEV) e microscopia ótica. As blendas com 22% de glicerol foram avaliadas também quanto a biodegradabilidade, utilizando a técnica de biodegradação aeróbia. A adição da zeína facilitou o pmcessamento das misturas, conforme o observado durante o processamento no reômetro de torque. A presença da zeína não afeta a cristalinidade do amido nas blendas e não ocorre a formação de novas estruturas cristalinas devido a mistura. As blendas amidolzeína apresentaram menor estabilidade térmica que o amido termoplástico e zeína plastificada separadamente e a estabilidade térmica das blendas diminuiu com o aumento do teor de glicerol. As propriedades mecânicas das blendas foram dependentes do teor de zeína e de glicerol. A adição de zeína na lenda provocou aumento no módulo de elasticidade e na resistência a tração e diminuição da deformação , enquanto que o gliceml provocou diminuição em todas estas propriedades. As blendas apresentaram-se imiscíveis em todas as composições estudadas. A zeína plastificada mostrou biodegradação mais acentuada que o amido termoplástico e as blendas apresentaram biodegradação intermediária entre o amido e a zeína.
Title in English
Development of polymer blends of zein and cornstarch
Keywords in English
Biodegradation
Mechanical properties
Natural polymers
Polymer blends
Starch
Thermal properties
Zein
Abstract in English
In this work were investigated blends from zein, which is a com protein, with com starch. The objective of this work was optimizing the polymers properties and their processing characteristics and looking for a structure-properties correlation of these blends. The mixtures of pure polymers and starchlzein blends were prepared using glycerol as plasticizer in a batch mixer connected to a torque rheometer. The zein content varied from 20 to 80% and three levels of glycerol were used, 22, 30 and 40 % of total starch plus zein weight, on a dry basis. The mixtures obtained were molded by compression at 160 OC. The blends were characterized by water absorption experiments, wide-angle X-ray diffraction, thermogravimetry (TG), differential scanning calorimetry (DSC), tensile test, dynamical mechanical thermal analysis (DMTA), scanning electron microscopy (SEM), optical microscopy. Additionally the biodegradability of starchtzein blends were evaluated by aerobic test. The torque behavior of the starchtzein blends shows that zein acts as a processing agent, reducing the melt viscosity of the mixture and facilitating the plasticization of starch. No evidence of the zein affecting the type or amount of crystal structure of thermoplastic starch was observed. The zein proved to be effective to reduce the water absorption of the blends. Mechanical properties of blends depends on the glycerol and zein contents. Young's modulus and ultimate tensile strength increase sharply with increasing zein content, while that the glycerol caused reduction on these properties. The blends were immiscible and phase invesion was observed. The results of biodegradation aerobic showed that after 45 days the zeína unfastened greater COz mass than the starch. This indicates that the zein biodegradation occurs more easily than the starch. The blends presented intermediate biodegradtion between the starch and the zein.
 
WARNING - Viewing this document is conditioned on your acceptance of the following terms of use:
This document is only for private use for research and teaching activities. Reproduction for commercial use is forbidden. This rights cover the whole data about this document as well as its contents. Any uses or copies of this document in whole or in part must include the author's name.
Publishing Date
2010-09-08
 
WARNING: Learn what derived works are clicking here.
All rights of the thesis/dissertation are from the authors
CeTI-SC/STI
Digital Library of Theses and Dissertations of USP. Copyright © 2001-2024. All rights reserved.