Handbook of Nucleating Agents

236 Pages·2016·27.92 MB·English

by  Wypych

Handbook of
Nucleating Agents
George Wypych, Editor
Toronto 2016
Published by ChemTec Publishing
38 Earswick Drive, Toronto, Ontario M1E 1C6, Canada
© ChemTec Publishing, 2016
ISBN 978-1-895198-93-5 (bound)
ISBN 978-1-927885-12-3 (epub)
Cover design: Anita Wypych
All rights reserved. No part of this publication may be repro-
duced, stored or transmitted in any form or by any means with-
out written permission of copyright owner. No responsibility is
assumed by the Author and the Publisher for any injury or/and
damage to persons or properties as a matter of products liabil-
ity, negligence, use, or operation of any methods, product ideas,
or instructions published or suggested in this book.
Library and Archives Canada Cataloguing in Publication
Wypych, George
Handbook of nucleating agents / George Wypych. -- First edition.
Includes bibliographical references and index.
Issued in print and electronic formats.
ISBN 978-1-895198-93-5 (bound).--ISBN 978-1-927885-12-3 (epub)
1. Polymers--Additives--Handbooks, manuals, etc. 2. Crystallization.
I. Title.
TP1142.W956 2016 668.9 C2015-907781-8
C2015-907782-6
Printed in Australia, United States and United Kingdom
1
Introduction
Nucleation is the initial process that occurs in the formation of a crystal from a solution, a
liquid, or a vapor, in which a small number of ions, atoms, or molecules become arranged
in a pattern characteristic of a crystalline solid, forming a site upon which additional parti-
cles are deposited as the crystal grows.1
Phase transformation begins with formation of a new phase in the supersaturated old
(mother) phase. The thermodynamic stability of the system requires continuity of the ther-
modynamic functions during the phase transformation, the change in the thermodynamic
potential occurring close to the transition point is by nature very small.2 Two possibilities
exist: either an infinitely small amount of a new phase appears, having different properties
than the old phase, or a new property appears.2 The first case is known as the first-order
phase transition because first derivatives of the thermodynamic potential are changed,
whereas the second case is known as the second-order phase transition because second
derivatives of the thermodynamic potential are changed.2
Nucleation is a step in the phase and state transitions, involved in such processes as
condensation, evaporation, crystallization, or melting, which are all the first-order transi-
tions. The first-order transition begins with a need to overcome a free-energy barrier to
create nucleus of the new phase on which additional elements of the system are deposited
to grow a crystalline phase.
Nucleation is either homogeneous or heterogeneous. Homogeneous nucleation is
very rare since it requires specially designed experiments in system, which does not have
any foreign elements. Although even in such cases, heterogeneous nucleation at container
walls or free surface occurs (e.g., formation of bubbles in champagne poured into glass).3
In homogenous system, the formation of the new phase solely depends on fluctuations
within the old phase. Assemblies of elements of the homogeneous system are formed in
kinetic equilibrium with free liquid system and they are dissolved back into old phase.
When temperature drops, more clusters are formed (metastable old phase becomes pres-
ent) and finally stable nucleus is created on which other particles are deposited forming
crystal. This means that the system needs to be brought into the metastable region to
reduce the phase transition barrier until it becomes of the same order as the thermal
energy, kT (where k is the Boltzmann constant and T is the absolute temperature).2
Heterogeneous nucleation occurs on the surface of impurities. These may exist in
any system or special additives can be added to facilitate heterogeneous nucleation. Any
interface with another material has potential importance for nucleation.3 Examples include
a free surface, the wall of a container, embedded particle, an interphase boundary in a liq-
uid or solid, and a grain or domain boundary in a solid.3 All such interfaces have positive
free energies.3 Heterogeneous nucleation faces much smaller barrier towards phase transi-
2 Introduction
tion. Rain, fog, ice and snow, salt crystallization by evaporation of sea water, and gas bub-
ble formation in mineral water—in addition to polymer processing—begin with the
nucleation of a new phase.
Polymeric materials during their production must undergo phase changes to be
formed into shapes required by their product design. For this reason, nucleation processes
are very essential for the production technology, economy of the production, and product
characteristics.
This book discusses use of nucleating agents to increase the production rate, modify
structure and morphology, and reduce haze of polymeric products with proper selection of
nucleating agents (or the so-called clarifying agents). Handbook of Nucleating Agents
brings analyses of important publications out of slightly less than 10,000 available today
referring to various aspects of action of nucleating agents. Also many relevant patents are
reviewed.
Sufficient understanding for proper use of nucleation technology requires analyses of
many aspect related to this subject. The book is divided into 14 chapters each of which
concentrates on the essential performance of nucleating agents. Chemical origin and
related properties of nucleating agents are analyzed in the general terms to highlight the
differences in their properties and thus mode of their action. The specific agents are dis-
cussed in Databook of Nucleating Agents which is published as a separate book to help
in selection of products available in the commercial markets and to analyze properties of
different products.
Many theoretical principles help in proper application of nucleating agents. One of
the important aspects is their effect on the rate and the degree of crystallization of poly-
meric matrices into which they have been introduced. Critical processes occur here during
crystallization process. Decrease of temperature alone already causes crystallization of
polymers, usually with formation of α-crystals. Addition of nucleating agent contributes
to formation of β-crystals which drive equilibrium of properties towards faster solidifica-
tion (possibility of speeding process of removal of parts from forms) or to better organiza-
tion of internal structure which translates to improved mechanical performance. Also,
addition of well selected nucleating agents helps to produce sufficiently small spherulites
that they do not interfere with light transmission thus help to produce materials having
high clarity.
Quality of contact between the nucleating agent and the matrix polymer affects effi-
ciency of its action. This will depend on properties of a pair polymer-agent and distribu-
tion of agent in the polymer matrix. Good wetting and absorption may lead to a complete
removal of barrier to nucleation between both phases.
Effect of concentration of nucleating agent and cooling rate are part of well designed
system, which is able to produce expected results, and able to increase nucleation effi-
ciency. Knowledge of the mechanisms of nucleation is also important aspect of selection
of nucleating agents for particular tasks.
Large segment of the book discusses use and selection of nucleating agents for dif-
ferent processing methods, different polymers and specific products. These sections con-
tain practical know-how on use of nucleating additives in different environments.
Introduction 3
This part is followed by chapters discussing effect of nucleating agents on mechani-
cal and physical properties of materials, important analytical methods used in their stud-
ies, and health and safety information in the relationship to application of nucleating
agents.
Chemical origins of nucleating agents are discussed in the next chapter. There are 20
chemical groups of nucleating agents which are either currently used as commercially
available additives or tried in experimental formulations. Each group is characterized by
range of properties characteristic for representatives of the group.
REFERENCES
1 Encyclopedia Britannica.
2 Nanev, C, The Theory of Nucleation, Handbook of Crystal Growth, 2nd Ed., Elsevier, 2015,
pp. 315-58.
3 Kelton, K F; Greer, A L, Heterogeneous nucleation, Nucleation in Condensed Matter, Vol. 15, Elsevier,
2010, pp. 165-226.
2
Chemical Origin of
Nucleating Agents
Twenty chemical groups of inorganic and organic chemical are involved in production of
nucleating agents. They include:
• acids
• amides
• carbon nanotubes
• graphene derivatives
• hydrazides
• inorganic materials
boron nitride
calcium carbonate
hydroxides
silica
talc
others
• masterbatches
• phosphate salts
• polymeric materials
• proprietary formulations
• salts of carboxylic acids
• sorbitol derivatives
• xylan esters
• others
Each group is discussed in a separate section below. The main output includes a table
containing properties of nucleating agents which belong to the particular group. The data
come from 300 generic and commercial nucleating agents. The data show the range of
properties which can be expected from products included in the group. To review data of
individual nucleating agents used by industry, a separate publication entitled Databook of
Nucleating Agents is available.
6 Chemical Origin of Nucleating Agents
2.1 ACIDS
2.1 Properties of acids
GENERAL PROPERTIES
Names: 2,5-Pyridine dicarboxylic acid; Glycine; L-Alanine; CAS #: 100-26-5; 56-40-6;
Poly–DL–alanine; L-Aspartic acid; Polyglycine; Polyglycolide; 56-41-7; 56-84-8; 25281-63-4;
Polylactide 25718-94-9; 26124-68-5;
26100-51-6
Synonims: isocinchomeronic acid; mixture of polycarbonic acids, inorganic carbonates, and fatty
acid derivatives; aminoacetic acid; aminosuccinic acid; poly(glycolic acid); polyoxyacetyl;
poly(L-lactic acid)
IUPAC names: pyridine-2,5-dicarboxylic acid; poly[oxy(1-oxo-1,2-ethanediyl)]
Purity, wt%: 98-98.5
PHYSICAL PROPERTIES
State: solid Color: white to off-white Odor: odorless
Melting point, oC: 232-270 Bulk density, kg/m3: 430-920 Density, g/cm3: 1.16-1.7
Volatility, wt%: 0.2% (105oC, 2h) Melt flow rate, g/10 min: 6-7
Solubility in water, wt%: soluble pH: 2.5-6.4
Solubility in solvents: methanol, acetone, acetic acid, ether
HEALTH AND SAFETY
Carcinogenicity: N (NTP, OSHA) Flash point, oC: 128.7
UN safety phrases: S22,S24/25 Oral rat, LD50, mg/kg: 7930
NFPA Flammability: 0-1 NFPA Health: 0-1 NFPA Reactivity: 0
USE
Manufacturers: Endex; generic
Outstanding properties: ice nucleation; biodegradable
Recommended for polymer: PBA, PLA, iPS, PVA Processing methods: extrusion
With decreasing cooling rate between 50 and 0.5 K s–1 the number of crystal nuclei
increases which enhances cold-crystallization on subsequent heating, and which delays
the formation and reduces the amount of additional nuclei during annealing of PLLA.1
The minimum half-time of crystallization is of the order of magnitude of few minutes and
increases with increasing molar mass.1 The nucleation mechanism is independent of tem-
perature in the range of 313 to 383K.2
REFERENCES
1 Androsch, R; Iqbal, N; Schick, C, Polymer, in press, 2015.
2 Androsch, R; Di Lorenzo, M L, Polymer, 54, 6882-85, 2013.
2.2 Amides 7
2.2 AMIDES
2.2 Properties of amides.
GENERAL PROPERTIES
Names: 1,3,5-Benzenetrisamide; Irgaclear; Light Amide; NJstar; CAS #: 51253-00-1;
N,N'-Bis(2-stearamidoethyl)sebacamide; N,N’-Dicyclohexyl- 60768-10-7;
2,6-naphthalene dicarboxamide; N-Tallow-4-toluenesulfon- 153250-52-3; 160535-46-6
amide; Rikaclear; Uniplex
Synonims: 1,3,5-benzene tricarboxamide; 1,3,5-tris (2, 2-dimethylpropanamide)-benzene;
ethylene bis stearamide; N,N'-bis(2-stearamidoethyl)sebacamide; N,N'-dicyclohexyl-2,6-naphtha-
lene dicarboxamide; (N,N',N''-tris[2-methylcyclohexyl]-1,2,3-propaneticarbooxamide)
IUPAC names: 1,3,5-benzenetricarboxamide; N,N'-bis[2-(2-aminoethyl)octadecanoyl]
decanediamide; 2-N,6-N-dicyclohexylnaphthalene-2,6-dicarboxamide;
N-alkyl toluene sulfonamide
Moisture content, %: 0.1-0.5 Purity, wt%: 99
PHYSICAL PROPERTIES
State: solid Color: white, yellow Acid number, mg KOH/g: 15
Boiling point, oC: 456-700 Melting point, oC: 78->400
Refractive index: 1.483-1.649 Bulk density, kg/m3: 100-400 Density, g/cm3: 0.92-1.4
Solubility in water, wt%; insoluble Volatility, wt%: 0.5
Surface tension, mN/m: 48.0-76.6 Vapor pressure, kPa: 0.279
HEALTH AND SAFETY
Flash point, oC: 200-248
REL/PEL, mg/m3: 5 (respirable fraction, OSHA), 15 (total dust, OSHA)
USE
Manufacturers: BASF, Recommended for polymer: PA, PBT, PET, PLA, iPP, PVDF
Kyoeisha Chemical,
New Japan Chemical, Unitex
Outstanding properties: excellent thermal stability with chemical resistance, β-crystal nucleating
agent, improves secondary processability, enhances shock resistance and heat resistance by lower-
ing the melting point of PP resins; clarifying agent eliminates plateout during extrusion, improves
the transparency, gloss, rigidity, flexural modulus, tensile strength
Typical applications: sheet, profiles Concentration used, wt%:
0.0015-0.3
Processing methods: extrusion, injection molding Food contact: yes
An aryl amide derivative (TMB-5) was used to nucleate the poly(l-lactide)/poly(d-
lactide) (PLLA/PDLA) blend.1 The selective nucleation of stereocomplex (sc) crystals
was observed.1 A sc crystal layer was found on the lateral surface of nucleating agent.1
REFERENCES
1 Xiong, Z; Zhang, X; Wang, R; de Vos, S; Wang, R; Joziasse, C A P; Wang, D, Polymer, 76, 98-114, 2015.
8 Chemical Origin of Nucleating Agents
2.3 CARBON NANOTUBES
2.3 Properties of carbon nanotubes.
GENERAL PROPERTIES
Names: CNT Regular; Nanocyl, Pyrograf CAS #: 1333-86-4
Synonims: single wall carbon nanotubes; multiwall carbon nanotubes
Purity, wt%: 90 Product content: 70-99% carbon, 10-30% oxide, 0.14% sulfur,
0.94% iron
PHYSICAL PROPERTIES
State: solid Color: black Odor: odorless
Particle size, μm: 0.45-100 (length, 0.3-150 nm (diameter) Melting point, oC: 3652-3697
Solubility in water, wt%: insoluble Bulk density, kg/m3: 40-870
Specific surface area, m2/g: 20-1000 Density, g/cm3: 1.3-2.1
Thermal conductivity, W/mK: 50-3500
HEALTH AND SAFETY
Autoignition temperature, oC: 610
Oral rat, LD50, mg/kg: >2000->5000
NFPA Flammability: 1 NFPA Health: 1-2 NFPA Reactivity: 0
USE
Manufacturers: Carbon Nano-material Technology; NanoLab; Applied Sciences
Recommended for polymer: PE, PCL, PLA, PP
Outstanding properties: a good nucleating agent as well as reinforcement, fast heterogeneous
crystallization, high electrical conductivity
Short chain branching in polyethylene decreases adsorbed polymer chain on the sur-
face of carbon nanotubes.1 Simulation study shows that the carbon nanotube seems to
increase more efficiently the polyethylene crystallinity in the case of the branched chains
than in the linear ones.1 The presence of surface groups on carbon nanotubes reduced their
ability to nucleate poly(L-lactic acid).2 At high supercooling, where homogeneous nucle-
ation is prevalent, the addition of carbon nanotubes does not affect the crystallization rate
of PCL.
REFERENCES
1 Jeronimo, K; Cruz, V L; Ramos, J; Vega, J F; Trujillo, M; Mueller, A J; Martinez-Salazar, J, Eur. Polym. J.,
56, 194-204, 2014.
2 Kiang, Y-Y; Xu, J-Z; Liu, X-Y; Zhong, G-L; Li, Z-M, Polymer, 54, 23, 6479-88, 2013.
3 Zhuravlev, E; Wurm, A; Poetschke, P; Androsch, R; Schmetzer, J W P; Schick, C, Eur. Polym. J.,
52, 1-11, 2014.
2.4 Graphene derivatives 9
2.4 GRAPHENE DERIVATIVES
2.4 Properties of graphene derivatives.
GENERAL PROPERTIES
Names: Fullerene; GnP Purity, wt%: 99-99.95
Synonims: graphene, graphene oxide nanosheet
Product content: C60 spherical allotrope of carbon, important property of C60 molecule is its
high symmetry; nanoparticles consist short stacks of graphene sheets having a platelet shape
PHYSICAL PROPERTIES
State: solid Color: black Odor: odorless
Specific surface area, m2/g: 750 Particle size, μm: 2
USE
Manufacturers: Nano-C; XG Science
Recommended for polymer: epoxy, PCBM, PLC, PLLA, PP
Outstanding properties: increase in fracture toughness, epitaxial crystallization
Typical applications: solar cells, medical applications, many industrial applications
Processing methods: injection molding Concentration used,
wt%: 0.01-0.25
The graphene nanosheets impede the movements of PCL chain and increase the sys-
tem viscosity, resulting in an evident increase of crystallization activation energy.1 The
nonisothermal cold crystallization behavior of PLLA was enhanced by the presence and
amount of graphene oxide.2
REFERENCES
1 Lv, C; Wu, D; Qiu, Y; Chen, J; Yao, X; Ding, K; Wei, N, Thermochim. Acta, 612, 25-33, 2015.
2 Zhao, H; Bian, Y; Li, Y; Han, C; Dong, Q; Dong, L; Gao, Y, Thermochim. Acta, 588, 47-56, 2014.