Evaluering van die hegting van elastomere van hoe-energie materiale
Date
1994
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : Stellenbosch University
Abstract
AFRIKAANSE OPSOMMING: 'n HTPB-gebaseerde nitramiensamestelling (Giet PBX) is saamgestel uit verskillende komponente naamlik die nitramien (RDX; HMX), 'n prepolimeer (HTPB), 'n kruisbinder, 'n plastiseerder, 'n antioksideermiddel en 'n katalis. Die chemiese samestellings wat hiervoor gebruik word is bewese en word ook in Dryfmiddelsamestellings gebruik. Die hegting tussen die polimeerbinder en die nitramien is egter nie optimaal nie en kan tot sensitiwiteitsprobleme aanleiding gee.
'n Komponent wat gebruik kan word om hierdie probleem te oorkom, is 'n bindmiddel. 'n Bindmiddel is 'n samestelling wat oor funksionele groepe beskik wat deur middel van chemiese of fisiese interaksie aan beide die binder en die nitramien bind.
Vyf verskillende potensiële bindmiddels is evalueer en die absolute effektiwiteit is aan die hand van meganiese sterkte analise toete (Instron apparaat) evalueer.
Alternatiewe evalueringstegnieke is ook ondersoek. Kontakhoekmetings met 'n Dinamiese Kontakhoekmetings Apparaat (Wilhelmy tegniek) is geneem en energie analise berekeninge gebaseer op verskillende teorieë (Kaelble, Penn en Zisman), is uitgevoer. FTIR-metings is ook uitgevoer ten einde meer oor die wyse van interaksie te wete kom.
Teorieë, wat op grond van meganiese sterkte metings en wiskundige manupilasie, voorspellings oor die hegtingspotensiaal van 'n komponent maak, is ook evalueer. Die teorieë van Nielsen, Markin en Hori is evalueer.
Die resultate van die standaard treksterkte toetse bewys Dantocol DHE as die beste bindmiddel vir 'n HTPB-nitramien samestelling te wees. HX-752 lewer ook relatief goeie resultate. Die siloksaan, TMSBM het die eienskappe van die PBX drasties verswak. Kaelble se Surface Energetics Analyses gekompineer met fraktuurmeganieka beginsels se voorspellings, gebaseer op desorpsiekontakhoekwaardes, korreleer kwalitatief baie goed met die meganiese sterkte resultate. Die tegniek se eenvoud en koste-effektiwiteit maak dit geskik vir soortgelyke ondersoeke.
Die resultatevan die alternatiewe meganiese sterkte metings korroleer ook relatief goed met die standaard toets en Dantocol DHE presteer ook in hierdie gevalle deurgaans goed. Die toetse, behalwe Hori se toets word egter nie, weens praktiese redes en koste-effektiwiteit redes vir gebruik aanbeveel nie.
FTIR-metings was weens plek oorvleuelings moeilik interpreteerbaar in sommige gevalle. Piek verskuiwings is wel vir die waterstofbinding waargeneem, wat dui dat daar wel waterstofbindings tussen die nitramien en bindmiddels is.
ENGLISH ABSTRACT: A HTPB-based nitramine composition (Cast-PBX) consists of different components namely, the nitramine (RDX; HMX), a prepolyemer (HTPB), a crosslinker, a plastisizer, anti-oxidising agent and a catalyst. The chemical components that are used are proven and also find application in propellant composition. The bonding between the polymer binder and the nitramine is not ideal and may lead to sensitivity problems. A bonding agent is used to overcome this problem. A bonding agent has functional groups that can react via chemical or physical methods with both the binder and the nitramine. Five potential bonding agents were evaluated and mechanical strength analysis (Instron apparatus) was used as absolute effectivity criteria. Aternative evaluation techniques were also investigated. Contact angles were measured with a Dynamic Contact angel measurement apparatus (Wilhelmy techniques) and energy analysis calculations based on various theories (Kaelble, Penn and Zisman) were done. To learn more about the type or way of interaction, FTIR measurements were done. The theories of Nielsen, Markin and Hori which are based on mechanical strength analysis and mathematical manipulations to predict the bonding potential of a component, were also investigated. The results of the standard tensile strength test shown Dantocol DHE to be the best bonding agent for a HTPB-nitramine composition. Based on the results, HX-752 proves to be a good alternative. The siloxane, TMSPM had a drastic weakening effect on the mechanical strength of the PBX. The predictions of Kaelble's Surface Energetic Analysis combined with fracture mechanic principles for the receding contact angle results, correlate qualitatively well with the tensile strength results. The simplicity and cost-effectivity of this technique makes it suitable for similar investigations. The results of the alternative mechanical strength measurement also correlate well with that of the standard test and Dantocol DHE's effectivity was proved. Except for the Hori-test, these tests are not, due to practical and cost effectivity reason, recommended. The FTIR-measurements were, because of the overlapping of peaks, difficult to interpret. Shifts in peaks were observed and it proves the existence of Hydrogen bondings between thenitramine and the bonding agents.
ENGLISH ABSTRACT: A HTPB-based nitramine composition (Cast-PBX) consists of different components namely, the nitramine (RDX; HMX), a prepolyemer (HTPB), a crosslinker, a plastisizer, anti-oxidising agent and a catalyst. The chemical components that are used are proven and also find application in propellant composition. The bonding between the polymer binder and the nitramine is not ideal and may lead to sensitivity problems. A bonding agent is used to overcome this problem. A bonding agent has functional groups that can react via chemical or physical methods with both the binder and the nitramine. Five potential bonding agents were evaluated and mechanical strength analysis (Instron apparatus) was used as absolute effectivity criteria. Aternative evaluation techniques were also investigated. Contact angles were measured with a Dynamic Contact angel measurement apparatus (Wilhelmy techniques) and energy analysis calculations based on various theories (Kaelble, Penn and Zisman) were done. To learn more about the type or way of interaction, FTIR measurements were done. The theories of Nielsen, Markin and Hori which are based on mechanical strength analysis and mathematical manipulations to predict the bonding potential of a component, were also investigated. The results of the standard tensile strength test shown Dantocol DHE to be the best bonding agent for a HTPB-nitramine composition. Based on the results, HX-752 proves to be a good alternative. The siloxane, TMSPM had a drastic weakening effect on the mechanical strength of the PBX. The predictions of Kaelble's Surface Energetic Analysis combined with fracture mechanic principles for the receding contact angle results, correlate qualitatively well with the tensile strength results. The simplicity and cost-effectivity of this technique makes it suitable for similar investigations. The results of the alternative mechanical strength measurement also correlate well with that of the standard test and Dantocol DHE's effectivity was proved. Except for the Hori-test, these tests are not, due to practical and cost effectivity reason, recommended. The FTIR-measurements were, because of the overlapping of peaks, difficult to interpret. Shifts in peaks were observed and it proves the existence of Hydrogen bondings between thenitramine and the bonding agents.
Description
Thesis (MSc)--Stellenbosch University, 1994.
Keywords
Elastomers, Adhesives, High energy materials