Influence of Molecular Structure of Components on Crystallinity and Mechanical Properties of LDPE/EPDM Blends

AbstractSpider silk attracts researchers from the most diverse fields, such as material science or medicine. However, still little is known about silk aside from its molecular structure and material strength. Spiders produce many different silks and even join several silk types to one functional unit. In cribellate spiders, a complex multi-fibre system with up to six different silks affects the adherence to the prey. The assembly of these cribellate capture threads influences the mechanical properties as each fibre type absorbs forces specifically. For the interplay of fibres, spinnerets have to move spatially and come into contact with each other at specific points in time. However, spinneret kinematics are not well described though highly sophisticated movements are performed which are in no way inferior to the movements of other flexible appendages. We describe here the kinematics for the spinnerets involved in the cribellate spinning process of the grey house spider, Badumna longinqua, as an example of spinneret kinematics in general. With this information, we set a basis for understanding spinneret kinematics in other spinning processes of spiders and additionally provide inspiration for biomimetic multiple fibre spinning.

Download Full-text

The molecular structure characteristics of long chain branched polypropylene and its effects on non-isothermal crystallization and mechanical properties

Polymer ◽

10.1016/j.polymer.2012.12.073 ◽

2013 ◽

Vol 54 (4) ◽

pp. 1455-1462 ◽

Cited By ~ 34

Author(s):

Wangyang Zhao ◽

Yajiang Huang ◽

Xia Liao ◽

Qi Yang

Keyword(s):

Molecular Structure ◽

Mechanical Properties ◽

Isothermal Crystallization ◽

Structure Characteristics ◽

Branched Polypropylene ◽

Long Chain ◽

Long Chain Branched Polypropylene

Download Full-text

Conversion of Lignocellulosic Biomass to Nanocellulose: Structure and Chemical Process

The Scientific World JOURNAL ◽

10.1155/2014/631013 ◽

2014 ◽

Vol 2014 ◽

pp. 1-20 ◽

Cited By ~ 141

Author(s):

H. V. Lee ◽

S. B. A. Hamid ◽

S. K. Zain

Keyword(s):

Molecular Structure ◽

Mechanical Properties ◽

Lignocellulosic Biomass ◽

Chemical Process ◽

Catalyst Design ◽

Natural Resistance ◽

Cellulose Crystallinity ◽

Biomass Recalcitrance ◽

Cellulose Accessibility ◽

High Cellulose

Lignocellulosic biomass is a complex biopolymer that is primary composed of cellulose, hemicellulose, and lignin. The presence of cellulose in biomass is able to depolymerise into nanodimension biomaterial, with exceptional mechanical properties for biocomposites, pharmaceutical carriers, and electronic substrate’s application. However, the entangled biomass ultrastructure consists of inherent properties, such as strong lignin layers, low cellulose accessibility to chemicals, and high cellulose crystallinity, which inhibit the digestibility of the biomass for cellulose extraction. This situation offers both challenges and promises for the biomass biorefinery development to utilize the cellulose from lignocellulosic biomass. Thus, multistep biorefinery processes are necessary to ensure the deconstruction of noncellulosic content in lignocellulosic biomass, while maintaining cellulose product for further hydrolysis into nanocellulose material. In this review, we discuss the molecular structure basis for biomass recalcitrance, reengineering process of lignocellulosic biomass into nanocellulose via chemical, and novel catalytic approaches. Furthermore, review on catalyst design to overcome key barriers regarding the natural resistance of biomass will be presented herein.

Download Full-text