On the effects of hydroxyl substitution degree and molecular weight on mechanical and water barrier properties of hydroxypropyl methylcellulose films

Author(s)

Otoni, Caio G. ^{[1, 2]} ; Lorevice, Marcos V. ^{[1, 3]} ; de Moura, Marcia R. ^[4] ; Mattoso, Luiz H. C. ^[1]

Affiliation

^[1] Embrapa Instrumentat, Nanotechnol Natl Lab Agr LNNA, Rua 15 Novembro 1452, BR-13560970 Sao Carlos, SP - Brazil

^[2] Univ Fed Sao Carlos, Dept Mat Engn, PPG CEM, Rodovia Washington Luis, Km 235, BR-13565905 Sao Carlos, SP - Brazil

^[3] Univ Fed Sao Carlos, Dept Chem, PPGQ, Rodovia Washington Luis, Km 235, BR-13565905 Sao Carlos, SP - Brazil

^[4] Sao Paulo State Univ, FEIS, Dept Phys & Chem, Av Brasil 56, BR-15385000 Ilha Solteira, SP - Brazil

• Document type: Journal article
• Source: Carbohydrate Polymers; v. 185, p. 105-111, APR 1 2018.
• Web of Science Citations: 5

Abstract

In line with the increasing demand for sustainable packaging materials, this contribution aimed to investigate the film-forming properties of hydroxypropyl methylcellulose (HPMC) to correlate its chemical structure with film properties. The roles played by substitution degree (SD) and molecular weight (M-w) on the mechanical and water barrier properties of HPMC films were elucidated. Rheological, thermal, and structural experiments supported such correlations. SD was shown to markedly affect film affinity and barrier to moisture, glass transition, resistance, and extensibility, as hydroxyl substitution lessens the occurrence of polar groups. M-w affected mostly the rheological and mechanical properties of HPMC-based materials. Methocel (R) E4 M led to films featuring the greatest tensile strength (ca., 67 MPa), stiffness (ca., 1.8 GPa), and extensibility (ca., 17%) and the lowest permeability to water vapor (ca., 0.9 g mm kPa(-1) h(-1) m(-2)). These properties, which arise from its longer and less polar chains, are desirable for food packaging materials. (AU)

• FAPESP's process: 13/14366-7 - Fruit and vegetable purees/biopolymer-based edible films reinforced with miniaturized cellulose fibers
• Grantee: Caio Gomide Otoni
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 14/23098-9 - Study and optimization of natural fiber-reinforced edible polymer biocomposites formulated with fruit and vegetable processing wastes
• Grantee: Caio Gomide Otoni
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)