scholarly journals Evaluation of the types of starch for preparation of LDPE/starch blends

2007 ◽  
Vol 50 (3) ◽  
pp. 361-370 ◽  
Author(s):  
Glória Maria Vinhas ◽  
Suzana Moreira de Lima ◽  
Lívia Almeida Santos ◽  
Maria Alice Gomes de Andrade Lima ◽  
Yêda Medeiros Bastos de Almeida
Keyword(s):  
Mechanical Properties ◽  
Cellular Growth ◽  
Degree Of Crystallinity ◽  
Thermal And Mechanical Properties ◽  
Different Types ◽  
Before And After ◽  
Starch Blends ◽  
Short Time ◽  
Physical And Chemical ◽  
The Degree Of Crystallinity

This study evaluated in relation the growth, and the amylolytic activity of mixed and isolated cultures of Phanerochaete chrysosporium and Talaromyces wortmanni on different types of starch. The thermal and mechanical properties in polyethylene/starch blends (proportion: 80/20 (w/w) before and after inoculation of the mixed cultures were evaluated. The regular starch Amidex 3 and the modified starch Fox5901 stood out in relation to the cellular growth and production of the amylase enzyme. In spite of the short time that the blends were exposed to the fungi, the microorganisms promoted physical and chemical changes in the structure of the blend, modifying its thermal and mechanical properties. The alteration of the degree of crystallinity and mechanical properties of the blends could be indications of the modification caused by the biodegradation process.

scholarly journals LMPP Effects on Morphology, Crystallization, Thermal and Mechanical Properties of iPP/LMPP Blend Fibres

2018 ◽  
Vol 26 (2(128)) ◽  
pp. 26-31 ◽  
Author(s):  
Munir Hussain ◽  
Feichao Zhu ◽  
Feichao Zhu ◽  
Bin Yu ◽  
Bin Yu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Properties ◽  
Elastic Modulus ◽  
Isotactic Polypropylene ◽  
Degree Of Crystallinity ◽  
Thermal And Mechanical Properties ◽  
Elongation At Break ◽  
Breaking Elongation ◽  
Low Modulus ◽  
The Degree Of Crystallinity

The thermal properties and morphological characterisation of isotactic polypropylene (iPP) homopolymer and its blends with low molecular low modulus polypropylene (LMPP) were studied. Firstly blends were prepared with variant LMPP contents, and their properties were characterised using SEM, DSC, XRD, and DMA. Later the mechanical properties of iPP/LMPP blend fibres were investigated. SEM results showed that the iPP/LMPP blends produced smoother surfaces when the LMPP content was increased, as well as the miscibility. All the Tg values with different LMPP percentages were in-between pure iPP and LMPP. The XRD results indicated the LMPP percentage decreased along with the degree of crystallinity of the iPP/LMPP blends (5% to 15%), which increased and then decreased as compared to pure iPP. The elongation at break increased when the LMPP content increased, with the maximum breaking elongation of the LMPP 25% blend reaching 12.95%, which showed great stretch-ability, whereas the elastic modulus of iPP/LMPP blends decreased.

scholarly journals Studies of properties of polypropylene/halloysite composites

2011 ◽  
Vol 13 (3) ◽  
pp. 61-65 ◽  
Author(s):  
Agnieszka Szczygielska ◽  
Jacek Kijeński
Keyword(s):  
Mechanical Properties ◽  
Thermal Properties ◽  
Polymer Composites ◽  
Degree Of Crystallinity ◽  
Mechanical And Thermal Properties ◽  
Thermal And Mechanical Properties ◽  
Polypropylene Composites ◽  
Modification Method ◽  
The Degree Of Crystallinity

Studies of properties of polypropylene/halloysite compositesThe results of the studies on the synthesis, mechanical and thermal properties of polypropylene composites with various amount of halloysite filler are presented. Halloysite (HNT) belongs to the silica type characterized by a two-layer 1:1 structure. This work was aimed to develop a method for the modification of halloysite in its prime use as a filler for polypropylene by extrusion. The composites contain 1, 3, 5 and 7 wt.% of HNT. The degree of crystallinity of the composites decrease with increasing halloysite content. The results confirm the expectations that composites of interesting physicochemical, mechanical and thermal properties can be obtained. The mechanical properties studied show that the filler modification method used leads to the synthesis of polymer composites of improved thermal and mechanical properties.

scholarly journals Effect of UV-Irradiation and Ozone Exposure on Thermal and Mechanical Properties of PLA/LDPE Films

2022 ◽  
Author(s):  
M. Podzorova
Keyword(s):  
Mechanical Properties ◽  
Ozone Exposure ◽  
Degree Of Crystallinity ◽  
Thermal And Mechanical Properties ◽  
Strength Parameters ◽  
Thermophysical Characteristics ◽  
Scanning Calorimetry ◽  
Wide Range ◽  
The Degree Of Crystallinity ◽  
Range Of Values

Abstract. The mechanical properties of polymer composites based on polylactide vary significantly over a wide range of values. It has been established that photodegradation of low-density polyethylene – polylactide blends occurs both in the amorphous and in the crystalline phase of the PLA matrix, which leads to deterioration of the mechanical properties of the studied mixtures. Ozonolysis affects the strength parameters of polylactide-polyethylene samples as well as photodegradation. By the differential scanning calorimetry it is determined that the melting point of polylactide decreases by 2-4 °C, the glass transition temperature - by 1-3 °C, while the degree of crystallinity increases by 3-6%. In the process of ozonolysis, the thermophysical characteristics of PLA/LDPE have changed.

scholarly journals The Structure and Mechanical Properties of the UHMWPE Films Modified by the Mixture of Graphene Nanoplates with Polyaniline

Polymers ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 23 ◽  
Author(s):  
Tarek Dayyoub ◽  
Aleksey Maksimkin ◽  
Sergey Kaloshkin ◽  
Evgeniy Kolesnikov ◽  
Dilus Chukov ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Mechanical Properties ◽  
Filler Content ◽  
Dynamic Mechanical Properties ◽  
Degree Of Crystallinity ◽  
Functionalized Graphene ◽  
Lamellar Crystal ◽  
The Degree Of Crystallinity ◽  
Heterogeneous Crystallization ◽  
Graphene Nanoplates

Highly oriented UHMWPE films were reinforced with functionalized graphene nanoplates (GNP). GNP was functionalized by deposition of polyaniline (PANI) on the GNP surface. The structure of GNP/PANI was studied by Raman spectroscopy, and the structure of xerogels and films based on UHMWPE was studied by DSC and SEM. PANI promotes the reduction of the GNP aggregation in the UHMWPE matrix and increases the degree of crystallinity due to heterogeneous crystallization. The new lamellar crystal structure has a high drawability. The highest value of the tensile strength 1330 MPa (an increase of 45%) was obtained with a filler content of 2 wt % GNP/PANI, and the highest value of Young’s modulus 41 GPa (an increase of 32%) was obtained with a filler content of 1 wt % GNP/PANI. The effect of GNP with PANI fillers on the dynamic mechanical properties of the UHMWPE films was discussed.

CONNECTION BETWEEN STRUCTURAL CHANGES OF IRRIADIATED POLYETHER ETHER KETONE AND MECHANICAL PROPERTIES

Tribologia ◽  
2018 ◽  
Vol 278 (2) ◽  
pp. 95-101
Author(s):  
Aneta NIEMIEC
Keyword(s):  
Mechanical Properties ◽  
Glass Transition ◽  
Structural Changes ◽  
Radiation Energy ◽  
Degree Of Crystallinity ◽  
Scanning Calorimetry ◽  
Polyether Ether Ketone ◽  
Ether Ketone ◽  
The Impact ◽  
The Degree Of Crystallinity

The article presents the results of research on the impact of structural changes in polyether ether ketone (PEEK) on its mechanical properties. The polymer was exposed to gamma radiation at a dose of 50 and 150 kGy, and the radiation energy was 4 MeV. Changes in the degree of crystallinity and the related changes in the glass transition and melting temperature for the polymer were determined by differential scanning calorimetry (DSC). Mechanical properties were determined using the micro-mentoring method. The tests showed a change in the degree of crystallinity in the range of several degrees and a significant increase in the glass transition temperature. In terms of mechanical properties, the reduction of hardness and Young’s modulus was observed. Observed changes, especially in terms of changes in the structure of the polymer under the influence of radiation, are difficult to explain, which requires conducting further research, especially in the range of irradiation parameters used. Further research is important because PEEK is used in many fields, especially in conditions conducive to corrosion and the influence of radiation.

Effect of Tension on Mechanical Properties and Structure of Aramid Fibers during Heat Treatment

2013 ◽  
Vol 774-776 ◽  
pp. 856-859
Author(s):  
Hong Peng Zhong ◽  
Ahmed DawElbeit ◽  
Hai Juan Kong ◽  
Chun Mao Kang ◽  
Mei Hua ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Molecular Weight ◽  
Surface Topography ◽  
Fiber Strength ◽  
Degree Of Crystallinity ◽  
Aramid Fibers ◽  
Weight Decrease ◽  
The Degree Of Crystallinity

The heat treatment was carried out to modify the aramid fibers, and the effect of tension on the mechanical properties and structure was investigated through Fiber Strength Equipment, viscosity, XRD and SEM . The results show that fibers，strength slightly decrease, but modulus increase significantly according to the increasing of tension at 480°C and 10s, and reach a maximum when the tension value is 300 g. After heat treatment, molecular weight decrease and the degree of crystallinity increase. SEM show that there is little effect on the surface topography of the fibers during treatment.

Particle Size Reduction of Biomaterials Using Cryogenic Milling Process

2005 ◽  
Vol 475-479 ◽  
pp. 2403-2406 ◽  
Author(s):  
Sang Mok Lee ◽  
Hoon Jae Park ◽  
Seung Soo Kim ◽  
Tae Hoon Choi ◽  
E.Z. Kim ◽  
...  
Keyword(s):  
Particle Size ◽  
Ball Milling ◽  
Xrd Analysis ◽  
Milling Process ◽  
Degree Of Crystallinity ◽  
Particle Size Reduction ◽  
Cryogenic Milling ◽  
Ball Milling Process ◽  
Before And After ◽  
The Degree Of Crystallinity

Reducing the particle size of drug materials down to submicron is an important matter in pharmaceutical industry. Cryogenic milling technology is one of the mechanical milling processes, which is mostly utilized in refining grain size of metal and ceramics at extremely low temperature environment. This technique has not been readily studied in application to medical and biotechnology. This paper, therefore, describes the application of cryogenic milling process to reduce particle size of Ibuprofen. The shape and size of the Ibuprofen particle before and after the cryogenic ball milling process were analyzed. XRD analysis was performed to examine a change in crystallinity of Ibuprofen by the cryogenic ball milling process. The results showed that the size of Ibuprofen particles was reduced to 1/10 or less of its initial size. The results also showed that the degree of crystallinity of Ibuprofen was slightly reduced after cryogenic ball milling with nitrogen.

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