Chemical modification of polypropylene with diisocyanates for improved gas barrier and mechanical properties

2009 ◽  
Vol 28 (4) ◽  
pp. 233-245 ◽  
Author(s):  
R. S. Jagadish ◽  
Baldev Raj ◽  
P. Srinivas
Keyword(s):  
Mechanical Properties ◽  
Chemical Modification ◽  
Gas Barrier

scholarly journals Double-Cross-Linked Networks Based on Methacryloyl Mucin

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1706
Author(s):  
Elena Olăreț ◽  
Brîndușa Bălănucă ◽  
Andra Mihaela Onaș ◽  
Jana Ghițman ◽  
Horia Iovu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aqueous Solution ◽  
Chemical Modification ◽  
Structural Modification ◽  
Aqueous Media ◽  
Cross Linking ◽  
Ph Values ◽  
Acid Aqueous Solution ◽  
Reaction Media ◽  
Double Cross

Mucin is a glycoprotein with proven potential in the biomaterials field, but its use is still underexploited for such applications. The present work aims to produce a synthesis of methacryloyl mucin single-network (SN) hydrogels and their double-cross-linked-network (DCN) counterparts. Following the synthesis of the mucin methacryloyl derivative, various SN hydrogels are prepared through the photopolymerization of methacrylate bonds, using reaction media with different pH values. The SN hydrogels are converted into DCN systems via supplementary cross-linking in tannic acid aqueous solution. The chemical modification of mucin is described, and the obtained product is characterized; the structural modification of mucin is assessed through FTIR spectroscopy, and the circular dichroism and the isoelectric point of methacryloyl mucin is evaluated. The affinity for aqueous media of both SN and DCN hydrogels is estimated, and the mechanical properties of the systems are assessed, both at macroscale through uniaxial compression and rheology tests and also at microscale through nanoindentation tests.

Research on Chemical Modification of Wood of Fast-Growing Poplar

2013 ◽  
Vol 749 ◽  
pp. 461-465
Author(s):  
De Jun Shen ◽  
Chang Hai Yu ◽  
Zhen Xing
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Structural Material ◽  
Chemical Modification ◽  
Orthogonal Test ◽  
Low Molecular Weight ◽  
Wood Structure ◽  
Optimum Conditions ◽  
Fast Growing ◽  
Performance Requirements

This topic is considered to modify the fast-growing Poplar to improve the properties, in order to fully meet the performance requirements for the structural material. This study aims to improve the dimensional stability and some other mechanical properties through impregnated with the low-molecular-weight PF resin. Through design orthogonal test in different mole ratio of Formaldehyde and Phenol, different amount of NaOH and PVA, we make PF resin to impregnate Poplar and pressing into laminated timber to measure bonding strength, MOR, MOE. The study indicated that: the optimum conditions of the low molecular weight PF resin for modify Poplar are: mole ratio of Formaldehyde and Phenol is 2.4, mole ratio of NaOH and phenol is 0.05, amount of PVA is 3% of the phenol. Under this condition Poplar specimen got the biggest increase in various properties and it can satisfy the requirements of the outdoor wood structure.

scholarly journals Influence of layering pattern of modified kenaf fiber on thermomechanical properties of epoxy composites

2019 ◽  
Vol 36 (1) ◽  
pp. 47-62
Author(s):  
AR Mohammed ◽  
MS Nurul Atiqah ◽  
Deepu A Gopakumar ◽  
MR Fazita ◽  
Samsul Rizal ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Chemical Modification ◽  
Epoxy Matrix ◽  
Epoxy Composites ◽  
Woven Composites ◽  
Fiber Reinforced ◽  
Kenaf Fiber ◽  
Kenaf Fibers ◽  
The Impact ◽  
Woven Kenaf

Natural fiber-reinforced composites gained considerable interest in the scientific community due to their eco-friendly nature, cost-effective, and excellent mechanical properties. Here, we reported a chemical modification of kenaf fiber using propionic anhydride to enhance the compatibility with the epoxy matrix. The incorporation of the modified woven and nonwoven kenaf fibers into the epoxy matrix resulted in the improvement of the thermal and mechanical properties of the composite. The thermal stability of the epoxy composites was enhanced from 403°C to 677°C by incorporating modified woven kenaf fibers into the epoxy matrix. The modified and unmodified woven kenaf fiber-reinforced epoxy composites had a tensile strength of 64.11 and 58.82 MPa, respectively. The modified woven composites had highest flexural strength, which was 89.4 MPa, whereas, for unmodified composites, it was 86.8 MPa. The modified woven fiber-reinforced epoxy composites showed the highest value of flexural modulus, which was 6.0 GPa compared to unmodified woven composites (5.51 GPa). The impact strength of the epoxy composites was enhanced to 9.43 kJ m−2 by the incarnation of modified woven kenaf fibers into epoxy matrix. This study will be an effective platform to design the chemical modification strategy on natural fibers for enhancing the compatibility toward the hydrophobic polymer matrices.

scholarly journals Effects of Chemical Modification on the Mechanical Properties of Calotropis Gigantea Fiber-reinforced Phenol Formaldehyde Biocomposites

2020 ◽  
Vol 26 (3) ◽  
pp. 295-299
Author(s):  
Sekar SANJEEVI ◽  
Athijayamani AYYANAR ◽  
Ramanathan KALIMUTHU ◽  
Sidhardhan SUSAIYAPPAN
Keyword(s):  
Mechanical Properties ◽  
Chemical Modification ◽  
Phenol Formaldehyde ◽  
Fiber Composites ◽  
Fiber Content ◽  
The Other ◽  
Fiber Reinforced ◽  
Calotropis Gigantea ◽  
Chemical Treatments ◽  
Treated Fiber

In this paper, the effects of three different chemical treatments on the mechanical properties of Phenol Formaldehyde (PF) composites reinforced with the Calotropis Gigantea Fibers (CGFs) were investigated based on the fiber content of the fibers. Composites were prepared by the untreated and treated fibers using the hand lay up technique and their mechanical properties were evaluated and compared. The results revealed that the composites show the greater mechanical properties at 40 wt.% for the untreated condition. Composites prepared with alkali treated fibers show the better mechanical properties as compared with the other treated fiber composites.

scholarly journals The effect of chemical modification of wood in ionic liquids on the supermolecular structure and mechanical properties of wood/polypropylene composites

Cellulose ◽  
2018 ◽  
Vol 25 (8) ◽  
pp. 4639-4652 ◽  
Author(s):  
Slawomir Borysiak ◽  
Aleksandra Grząbka-Zasadzińska ◽  
Majka Odalanowska ◽  
Andrzej Skrzypczak ◽  
Izabela Ratajczak
Keyword(s):  
Mechanical Properties ◽  
Ionic Liquids ◽  
Chemical Modification ◽  
Supermolecular Structure ◽  
Polypropylene Composites
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