1、PUBLISHED DOCUMENTPD CEN/TR 15351:2006Plastics Guide for vocabulary in the field of degradable and biodegradable polymers and plastic itemsICS 83.080.01g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g4
2、0g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58PD CEN/TR 15351:2006This Published Document was published under the authority of the Standards Policy and Strategy Committee on 30 November 2006 BSI 2006ISBN 0 580 49611 2National forewordThis Published Document was published by BSI. It is the UK i
3、mplementation of CEN/TR 15351:2006. The UK participation in its preparation was entrusted to Technical Committee PRI/82, Thermoplastic materials.A list of organizations represented on PRI/82 can be obtained on request to its secretary.This publication does not purport to include all the necessary pr
4、ovisions of a contract. Users are responsible for its correct application.Amendments issued since publicationAmd. No. Date CommentsTECHNICAL REPORTRAPPORT TECHNIQUETECHNISCHER BERICHTCEN/TR 15351October 2006ICS 83.080.01English VersionPlastics - Guide for vocabulary in the field of degradable andbio
5、degradable polymers and plastic itemsPlastiques - Guide pour le vocabulaire dans le domaine despolymres et des produits plastiques dgradables etbiodgradablesKunststoffe - Leitfaden fr Begriffe im Bereich abbaubarerund bioabbaubarer Polymere und KunststoffteileThis Technical Report was approved by CE
6、N on 16 January 2006. It has been drawn up by the Technical Committee CEN/TC 249.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Nethe
7、rlands, Norway, Poland, Portugal, Romania,Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2006 CEN All rights of exploitation in
8、any form and by any means reservedworldwide for CEN national Members.Ref. No. CEN/TR 15351:2006: E2 Contents Page Foreword3 Introduction .4 1 Scope 5 2 Analysis of the alteration stages and mechanisms .5 2.1 Alteration stages5 2.2 Degradation mechanisms .6 3 Basic situations to be distinguished .7 3
9、.1 Individualised situations.7 3.2 Correlation to terms.8 4 The actual situations .8 4.1 Heterogeneous degradation.8 4.2 Formulated plastics.9 4.3 Qualifiers 9 5 Vocabulary11 5.1 Axioms for the vocabulary11 5.2 Terms and definitions. 11 Annex A (informative) Terms and definition listed in alphabetic
10、al order15 CEN/TR 15351:20063 Foreword This document (CEN/TR 15351:2006) has been prepared by Technical Committee CEN/TC 249 “Plastics”, the secretariat of which is held by IBN/BIN. CEN/TR 15351:20064 Introduction Today, there are several sectors of human activity that can take advantage of degradab
11、le and biodegradable polymers, polymeric materials and items, namely the sectors of biomedical, pharmaceutical, packaging, agricultural, and environmental applications. Although they appear very much different at first sight, these applications have some common characteristics: the necessity to deal
12、 with the polymeric wastes when a macromolecular material or compound is to be used for a limited period of time, the fact that living systems have some similarities in the sense that they function in aqueous media, they involve cells, membranes, proteins, enzymes, ions, etc, the fact that living sy
13、stems can be dramatically perturbed by toxic chemicals, especially low molar mass ones, Another characteristic of degradable polymeric compounds is that each sector of applications has developed its own science and thus its own terminology. In particular, surgeons, pharmacists and environmentalists
14、do not assign the same meaning to a given word. For instance, “biomaterial” means “therapeutic material” for people working in the biomedical sector whereas it means material of renewable origin for specialists working in the sector of exploitation of renewable resources. The field of norms is anoth
15、er source of examples. Norms related to degradation, and/or biodegradation in these different sectors, have introduced definitions independently. The resulting mismatching and inappropriate use often lead to misunderstanding and confusion. Because human health and environmental sustainability are mo
16、re and more interdependent and, because science, applications, and norms are developed in each of these sectors, it is urgent to harmonise the terminology or to define a specific terminology when a general one is not available, so that they can be proposed to international normative organisations. S
17、uch a task should be based on scientific and mechanistic considerations. The present technical report is an attempt to set up a common and simple terminology applicable in the various domains where degradation, biodegradation, bioassimilation, and biorecycling are major academic and industrial goals
18、. It is worth noting that elimination from the human (or animal) body of high molecular weight compounds is not possible unless macromolecules are degraded to low molar mass molecules. Indeed, skin, mucosa and kidney are very efficient barriers that keep high molar mass molecules entrapped in the pa
19、renteral compartments. As for the environmental life, eliminating a waste from the planet is not possible, so far. Therefore, any product or chemical that is not recycled or biorecycled is going to be stored in one way or another, i.e. as such or as biostable residue of degradation. CEN/TR 15351:200
20、65 1 Scope This guide provides the vocabulary to be used in the field of polymers and plastic materials and items. The proposed terms and definitions are directly issued from a scientific and technical analysis of the various stages and mechanisms involved in the alteration of plastics up to mineral
21、ization, bioassimilation and biorecycling of macromolecular compounds and polymeric products; i.e polymeric items. NOTE The proposed vocabulary is intended also to be in agreement with a terminology usable in various domains dealing with time limited plastic applications, namely biomedical, pharmace
22、utical, environmental, i.e., in surgery, medicine, agriculture, or plastics waste management. 2 Analysis of the alteration stages and mechanisms 2.1 Alteration stages If one looks carefully at what can happen when a polymeric item is in contact with a living system, regardless of the living system (
23、animal body, plant, micro-organisms or the environment itself), one finds different levels of alterations. These various levels are shown in Figure 1. Figure 1 The levels of alteration for a polymeric device From this schematic presentation it appears that the formation of tiny fragments or dissolut
24、ion does not necessarily correspond to macromolecule breakdown. Actually it reflects the disappearance of the initial device only. Whether the macromolecules that formed the original polymer-based item remain intact or are chemically cleaved with decrease of molar mass needs to be distinguished by s
25、pecific words. This is DIFFERENT LEVELS OF ALTERATIONfragmentsSolubilizedmacromoleculesMacromoleculefragmentsCO2+ H2O + biomassorFragmentationDissolutionErosionInitialorCEN/TR 15351:20066 important in the case of an animal body because of the retention of high molar mass molecules mentioned above. I
26、n the environment, solid fragments of a polymeric device (regardless of whether the particles are visible or not) may also be recalcitrant. Similarly, macromolecules that are dispersed or dissolved in outdoor water may be absorbed by minerals and stored there, or may reach the underground water, thu
27、s resulting in dispersion as long lasting waste in Nature. Macromolecule breakdown to “biostable” (i.e. could not be biodegraded further to minerals and biomass) small molecules is a third stage of degradation where low molar mass molecules may be generated that can be much more toxic than the origi
28、nal high molar mass ones. This remark raises the problem of the interactions of the degradation products with living systems. This problem is solved in the biomedical field by the use of the term “biocompatibility”. In the case of the environmental applications, there is not an equivalent word. One
29、could extend the use of the term “biocompatibility” to express that degradable polymeric items and their degradation products have no detrimental effect on relevant living systems. Whether the generated low molar mass degradation by-products can be bioprocessed further, i.e. up to bioassimilation, o
30、r their breakdown stops at intermediate stages where the generated degradation by-products are biostable needs also to be distinguished by specific words. The last stage of degradation is complex in the sense that it includes the formations of biomass, of CO2+ H2O and of some other compounds occasio
31、nally, e.g. CH4in the case of anaerobic biodegradation. Again, the formation of (CO2+ H2O) and of other inorganic residues that reflect the involvement of biochemistry in the macromolecule degradation should be distinguished from the biomass formation that shows that degradation by-products have bee
32、n bioassimilated by the degrading cells. It is important to note that photooxidation of some polymers can yield CO2in the absence of microorganisms. 2.2 Degradation mechanisms Another fundamental discussion concerns the routes that can lead from a polymeric item to the ultimate stage, namely mineral
33、isation + biomass formation. Actually, there are two main routes that are shown in Figure 2. Figure 2 The two general routes leading to bioassimilation POLYMERICCOMPOUNDSEnzymes + Cells ChemistryBiochemistry Low molar massby-productsEnzymes+CellsCO2 + H2OBiomassCEN/TR 15351:20067 a) Cell-mediated po
34、lymer degradation The left-hand side route corresponds to the attack of cells on a polymeric item or macromolecule followed by biochemical processing of the degradation products as a result of enzymatic reactions. This route requires the presence of appropriate enzymes and thus of specific cells und
35、er viable conditions (atmosphere, water, nutrients). In nature, enzymes cannot be found without the presence of living cells. In other words, no life-allowing conditions, no degradation by living systems. This raises the problem of degradation tests carried out under lab conditions with commercially
36、 available isolated enzymes. Are these isolated enzymes to be considered as causing degradation by a living system (despite the absence of the microorganisms that the enzymes are issued from) or by simple chemical degradation in the presence of a non-viable catalytic system? This question is fundame
37、ntal. It has to be solved by appropriate terminology in order to avoid confusion in literature. b) Chemistry-mediated polymer degradation The right hand side route differs from that of the left-hand side in the sense that the breakdown of polymer-based items and macromolecules depends on chemical pr
38、ocesses. Therefore, only the generated small molecules have to be eliminated through biochemical pathways. Here the conditions required to trigger chemical degradation are necessary (light, water, oxygen, heat). No triggering phenomenon, no degradation. On the other hand, living cells have to be pre
39、sent to ensure the biochemical processing of the low molar mass molecules formed from the macromolecules of the original polymeric item. Therefore, words are necessary to distinguish these routes. c) Combination If one combines the several levels of degradation with these two different routes, it is
40、 again obvious that a number of specific words are required to distinguish the various possibilities. It is worth noting that, any material is unstable when in contact with living systems for a long period of time and therefore, the terminology has to be limited to the desired degradation of polymer
41、ic items in contrast to the undesired degradation that any material eventually undergoes under the influence of use and ageing. 3 Basic situations to be distinguished 3.1 Individualised situations Let us first consider each possibility separately, though they can overlap to some extent: alteration o
42、f a polymeric item with or without disappearance in the absence of macromolecule cleavage due to breakdown to small solid fragments due to dissolution of macromolecules alteration of a polymer-based item with macromolecule cleavage due to non-enzymatic chemical phenomena due to abiotic enzymatic phe
43、nomena due to cell-mediated degradation with formation of biostable residues, regardless of the mechanism of degradation CEN/TR 15351:20068 3.2 Correlation to terms There is the need of distinguishing these various stages and phenomena that are usually referred to inconsistently as degradation or bi
44、odegradation. A means has to be found and accepted to differentiate the physical breakdown of a polymeric item without macromolecule cleavage from the physical breakdown of this polymeric item due to chemical macromolecule cleavage. It is proposed to use the already introduced axiom saying that for
45、macromolecular materials or systems that deteriorate acceptably in one way or another, degradation means alteration of macromolecules via chemical cleavage of the main chain. To technologists, this normally means “deterioration of technical performance, but to scientists it generally means “decrease
46、 of molar mass by chemical cleavage of the main chain”, which may be but not necessarily related to technical performance. The latter definition will be used in the present work. From there, biodegradation is defined as the alteration of macromolecules with chain cleavage caused by cells regardless
47、of their type (human or animal, vegetal, microbial or fungal). This biodegradation can result from cell enzymatic activity as well as from chemical reactions that can occur locally below a cell adhering to a polymeric surface because of the presence of some released non-enzymatic compounds (acids fo
48、r instance). Under these conditions, degradation in the presence of isolated enzymes under laboratory conditions cannot be considered as biodegradation and the distinction has to be made clearly. The biodegradation of a polymeric item has to be related to a measurable phenomenon. The production of C
49、O2and CH4for anaerobic process, or the consumption of O2are usually considered but they do not take into account the formation of biomass. NOTE It is worth noting that, under the above conditions, the terms degradation and biodegradation give information on the mechanism of chain cleavage but do not reflect the fate of the degradation by-products. “Fragmentation” can be selected to reflect a degradation observed at the physical level (visually or through physical measurements) which yields fragments of the original material regardless of the mechanism. I
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