Natural latex rubber condoms. Requirements and test methods

2015 ◽  
Keyword(s):  
Test Methods ◽  
Natural Latex Rubber ◽  
Latex Rubber

scholarly journals THE EFFECT OF LEATHER FIBERS ON VULCANIZATION BEHAVIOR OF NATURAL RUBBER

2018 ◽  
Vol 55 (1B) ◽  
pp. 85
Author(s):  
Le Thuy Hang
Keyword(s):  
Natural Rubber ◽  
Fiber Content ◽  
Primary Research ◽  
Maximum Torque ◽  
Research Results ◽  
Natural Latex Rubber ◽  
Latex Rubber

This paper shows the primary research results of the effect of the leather fibers on the vulcanization of natural rubber (NR). The fibers used in this research were prepared by grinding waste leather scraps of Vietnam shoe making company. Leather fibers (LFs) and natural latex rubber were mixed together at various rates by a stirring machine.  The obtained composites of natural rubber containing leather fibers were dried at pleasant condition prior to the analysis. Vulcanization behavior of the samples was clarified using a moving die rheometer. The vulcanization temperature as 120 °C is found to be the appropriate temperature for the NR/LFs composite. The increasing of minimum and maximum torque with the increasing of leather fiber content shows the improving in stiffness of natural rubber with the presence of leather fibers. Regarding to curing curves, 40 wt% promises to be the optimal leather fiber content to reinforce natural rubber.

Reinforcement of Natural Latex Rubber by Carbon Black and Ionizing Radiation

1962 ◽  
Vol 35 (4) ◽  
pp. 848-856 ◽  
Author(s):  
A. Lamm ◽  
G. Lamm
Keyword(s):  
Mechanical Properties ◽  
Thermal Treatment ◽  
Ionizing Radiation ◽  
Carbon Black ◽  
Aqueous Dispersion ◽  
Reinforcing Effect ◽  
Radical Nature ◽  
Natural Latex Rubber ◽  
Excellent Source ◽  
Latex Rubber

Abstract The study of the reinforcement of rubber by carbon black has made it possible to establish the radical nature of the interaction, thus explaining why, in the latex phase and in the absence of sources of radicals, the reinforcing effect of carbon black does not exist and why it has been possible up to the present to obtain it only by mastication of the solid rubber in the presence of black. Irradiation, an excellent source of radicals, should in latex systems lead to a reinforcement of rubber by black. The experiments carried out appear to prove this. Irradiation of the latex and the black in aqueous dispersion, followed by a mixture of the two constituents which is then poured out on a plate, dried and subjected to moderate thermal treatment, makes it possible to obtain mechanical properties which are definitely superior to those of films prepared without irradiation and of films vulcanized with sulfur.

Quality Improvement and Characteristics of Polyhydroxyalkanoates (PHAs) and Natural Latex Rubber Blends

2013 ◽  
Vol 334-335 ◽  
pp. 49-54 ◽  
Author(s):  
Pakawadee Kaewkannetra ◽  
Sarunya Promkotra
Keyword(s):  
Tensile Strength ◽  
Elastic Modulus ◽  
Thermal Characterization ◽  
Degree Of Crystallinity ◽  
Scanning Calorimetry ◽  
Combination Technique ◽  
Rubber Blends ◽  
Natural Latex Rubber ◽  
High Degree ◽  
Latex Rubber

Biopolymers of hard, brittle and low flexible polyhydroxyalkanoates (PHAs) and a soft and high elastic natural-latex rubber are blended at room temperature by using a combination technique. Concentrations of the PHAs solution are constituted at 1%, 2% and 3% w/v and mingled with fresh natural latex in different ratios (PHAs : Latex Rubber = 0:10, 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2, 9:1 and 10:0). After vigorous blending, forming polymeric sheets leave a dried-film pattern. Only the best 3 different ratios (4:6, 5:5 and 6:4) are selected by evaluating morphological-based information. These lead to actually define and characterize for their morphological and mechanical properties. The morphological attributes are exemplified by polarized optical microscopy and X-ray diffractometry (XRD) while the thermal characterization is determined by differential scanning calorimetry (DSC). Morphological analysis for the criterion of blending achievement indicated that there is a significant relationship among porosity, texture and shrinkage. The porosity shows obviously low to high for gradually increasing PHAs and decreasing the latex. Thus, dense texture and shrinkage relate to blending compositions between PHAs and latex. The XRD and DSC reveal certain aspects of decreasing crystallinity arising from enhancing of the latex content. A high degree of crystallinity and melting temperature relates to greater PHAs ratio. The mechanical investigations have revealed complex localization patterns of tensile strength and elastic modulus. The more PHAs concentration at 2% w/v indicates the greater elastic modulus than 3% and 1% w/v. Significant differences are found on polymeric composites of mechanical analyses between PHAs and natural latex. The constituted superiority in the ratio of 5:5 significantly differs in extension to break. Additionally, both tensile strength and elastic modulus of 2% w/v PHAs present the maximum value among them.

Laboratory proficiency in susceptibility testing of Helicobacter pylori using agar dilution and E test methods

2001 ◽  
Vol 120 (5) ◽  
pp. A586-A587
Author(s):  
L BEST ◽  
S JO ◽  
V VANZANTEN ◽  
D HALDANE ◽  
V LOO ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Susceptibility Testing ◽  
Test Methods ◽  
Agar Dilution

Scientific and Standardization Committee Communications Comparison of Test Methods for the Lupus Anticoagulant: International Survey on Lupus Anticoagulants-I (ISLA-1)

1990 ◽  
Vol 64 (03) ◽  
pp. 478-484 ◽  
Author(s):  
Thomas Exner ◽  
Douglas A Triplett ◽  
David A Taberner ◽  
Margaret A Howard ◽  
E Nigel Harris
Keyword(s):  
Lupus Anticoagulant ◽  
Test Methods ◽  
Positive Sample ◽  
Direct Proportion ◽  
Clotting Time ◽  
Preliminary Screening ◽  
Activated Platelets ◽  
Tissue Thromboplastin ◽  
Kaolin Clotting Time ◽  
Induced Defects

SummarySix lyophilized plasma samples were sent to 20 “expert” laboratories for assessment of lupus anticoagulant (LA). Four samples contained pooled LA of graded potency mixed with aged normal plasma. One contained LA plus cephalin phospholipid and one contained a nonspecific venom anticoagulant. Sixteen methods were used overall with some participants using up to 8 methods. Results were scored in regard to the known potencies of LA in the samples and other known induced defects.Activated partial thromboplastin time (APTT) tests used by most participants for preliminary screening were relatively sensitive, but non-specific. Platelet or phospholipid neutralization procedures (PNP) appeared to be sensitive and specific but showed a non-linear response to increased LA content. Kaolin clotting time (KCT) tests showed the most sensitive response to increased LA content but the weaker LA were not scored as abnormal by most laboratories as the samples may have contained platelet fragments. Other commonly used tests such as the tissue thromboplastin inhibition (TTI) test and the dilute Russell’s viper venom test (DRVVT) were carried out somewhat inconsistently. The variability in performance of tests in different laboratories indicates that standardization of methodology is urgently required.Generally it seemed that most clotting tests were “bypassed” by the addition of phospholipid to a known LA-positive sample in apparently direct proportion to their sensitivity. Sample preparation, especially prevention of contamination with activated platelets is a vital preliminary part in the assay of LA.

A method for measuring the in-plane compressive strength and the compression behavior of coating layers

TAPPI Journal ◽  
2011 ◽  
Vol 10 (7) ◽  
pp. 29-34
Author(s):  
TEEMU PUHAKKA ◽  
ISKO KAJANTO ◽  
NINA PYKÄLÄINEN
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Calcium Carbonate ◽  
Coating Layer ◽  
Test Methods ◽  
Coating Films ◽  
Precipitated Calcium Carbonate ◽  
Coating Color ◽  
Mineral Coatings ◽  
Styrene Butadiene

Cracking at the fold is a quality defect sometimes observed in coated paper and board. Although tensile and compressive stresses occur during folding, test methods to measure the compressive strength of a coating have not been available. Our objective was to develop a method to measure the compressive strength of a coating layer and to investigate how different mineral coatings behave under compression. We used the short-span compressive strength test (SCT) to measure the in-plane compressive strength of a free coating layer. Unsupported free coating films were prepared for the measurements. Results indicate that the SCT method was suitable for measuring the in-plane compressive strength of a coating layer. Coating color formulations containing different kaolin and calcium carbonate minerals were used to study the effect of pigment particles’ shape on the compressive and tensile strengths of coatings. Latices having two different glass transition temperatures were used. Results showed that pigment particle shape influenced the strength of a coating layer. Platy clay gave better strength than spherical or needle-shaped carbonate pigments. Compressive and tensile strength decreased as a function of the amount of calcium carbonate in the coating color, particularly with precipitated calcium carbonate. We also assessed the influence of styrene-butadiene binder on the compressive strength of the coating layer, which increased with the binder level. The compressive strength of the coating layer was about three times the tensile strength.

An evaluation of ECT sample height for small flute board grades and Box Manufacturer’s Certification compliance

TAPPI Journal ◽  
2009 ◽  
Vol 8 (6) ◽  
pp. 24-28
Author(s):  
CORY JAY WILSON ◽  
BENJAMIN FRANK
Keyword(s):  
Compressive Strength ◽  
Compressive Load ◽  
Test Sample ◽  
Test Methods ◽  
Test Method ◽  
Initial Development ◽  
Sample Height ◽  
Relationship Of ◽  
The Relationship ◽  
Corrugated Fiberboard

TAPPI test T811 is the specified method to ascertain ECT relative to box manufacturer’s certification compliance of corrugated fiberboard under Rule 41/ Alternate Item 222. T811 test sample heights were derived from typical board constructions at the time of the test method’s initial development. New, smaller flute sizes have since been developed, and the use of lighter weight boards has become more common. The T811 test method includes sample specifications for typical A-flute, B-flute, and C-flute singlewall (and doublewall and triplewall) structures, but not for newer thinner E-flute or F-flute structures. This research explores the relationship of ECT sample height to measured compressive load, in an effort to determine valid E-flute and F-flute ECT sample heights for use with the T811 method. Through this process, it identifies challenges present in our use of current ECT test methods as a measure of intrinsic compressive strength for smaller flute structures. The data does not support the use of TAPPI T 811 for ECT measurement for E and F flute structures, and demonstrates inconsistencies with current height specifi-cations for some lightweight B flute.

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