Polycycloolefins resistant to solvents

Thermoset polycycloolefins are obtained by polymerzing at an elevated temperature a cycloolefin containing at least one norbornene group in the presence of a metathesis catalyst system and also in the presence of an effective amount of a polyfunctional cycloolefin crosslinker containing at least one norbornene group, but preferably two or more, with two or more unsaturated sites, preferably two or more double bonds.

BACKGROUND OF THE INVENTION 
It is known that cycloolefins containing a norbornene moiety can be 
polymerized in the presence of an alkylaluminum halide cocatalyst and a 
molybdenum or tungsten halide catalyst. This is accomplished by mixing a 
cycloolefin with a solvent and charging the mixture to a reactor. A 
molecular weight modifier is charged to the reactor followed by cocatalyst 
and catalyst. The catalyst is added as a solution in an alkylester of a 
saturated carboxylic acid, since it is insoluble in the monomer. 
Polymerization is conducted by ring opening at 0.degree. to 200.degree. C. 
and is completed in less than 2 hours after shortstopping with an alcohol. 
The reaction product is a smooth, viscous material of a honey-like 
consistency comprising polycycloolefin dissolved in the solvent. 
U.S. Pat. No. 4,380,617 to Minchak et al discloses the use of 
organoammonium molybdates and tungstates in the polymerization of 
cycloolefins. The organoammonium molybdate and tungstate catalysts are 
soluble in cycloolefins and therefore, do not require the use of an 
alkylester solvent, which caused problems in the prior art polymerization. 
Furthermore, since the catalyst is soluble in cycloolefins, polymerization 
of the cycloolefins in bulk is thereby facilitated. 
Although the function of the catalyst is improved by using organoammonium 
molybdates or tungstates instead of molybdenum or tungsten halides, the 
cocatalyst is still too active and results in rapid polymerization of 
cycloolefins which is difficult to control. U.S. Pat. No. 4,426,502 
discloses the use of alkoxy-aluminum halide or aryloxyaluminum halide 
cocatalysts. By introducing an alkoxy or an aryloxy group into the 
cocatalysts, it is thus possible to diminish the reducing power of the 
cocatalysts so that a controlled polymerization can be conducted. The use 
of such cocatalysts makes it possible to prepare a monomer mix at room 
temperature which is inactive and then to polymerize the monomer mix at an 
elevated temperature, as by injecting it into a pre-heated mold. It is 
particularly significant that diminishing the reducing power of the 
cocatalysts by this method does not retard the rate of polymerization in a 
real sense. This development makes it possible to polymerize cycloolefins 
in bulk or by reaction injection molding, which is a form of bulk 
polymerization. 
Polycycloolefins have found numerous applications in the electronics 
industry, however, the presence of a halogen in the system cannot be 
tolerated since halogen can corrode or have other adverse electrical 
effects and render a circuit unreliable or inoperable. U.S. patent 
application entitled "Polymerization of Cycloolefins With Halogen-Free 
Cocatalysts" by inventors Minchak et al, discloses halogen-free 
cocatalysts which can be used with halogen-free catalysts in a 
halogen-free system to polymerize cycloolefins. The halogen-free 
cocatalysts are characterized by the use of an alkylaluminum, specifically 
trialkylaluminum, cocatalyst in conjunction with a modifier compound 
selected from trialkyl tin oxides, with or without a hindered phenol. The 
cocatalyst can also be devoid of a modifier compound in which instance, it 
includes a trialkylaluminum which is used together with a hindered phenol. 
SUMMARY OF THE INVENTION 
This invention pertains to the use of a minor amount of a polyfunctional 
crosslinking cycloolefin containing at least two norbornene structures 
each containing at least one unsaturated bond, or a norbornadiene, in a 
polymerization system containing a cycloolefin monomer, a catalyst and a 
cocatalyst whereby upon polymerization of the cycloolefin monomer, a cured 
or cross-linked, thermoset polycycloolefin is obtained having a swell 
index of less than about 10. Furthermore, the degree of crosslinking can 
be easily controlled by the type and amount of the crosslinker employed to 
regulate the properties of the resulting polymer. 
DETAILED DESCRIPTION OF THE INVENTION 
This invention is directed to the use of certain polyfunctional 
cycloolefins as crosslinkers by incorporating such crosslinkers in the 
monomer mix and polymerizing such monomer mix at an elevated temperature 
whereby a crosslinked polymer is obtained. As used herein, the term 
"polyfunctional" means that the crosslinking monomer has two or more 
unsaturated sites or double bonds in its structure, preferably two 
bicycloheptene structures, fused or not. The crosslinked polymers are 
resistant to solvents in the sense that they are insoluble in solvents or 
swell therein to the extent of having a swell index of less than about 10, 
preferably a swell index of less than about 5. 
The swell index is determined by placing 0.1 gram of a crosslinked 
polycycloolefin sample in 25 mls of toluene and holding it in toluene for 
a period at least 5 days. Thereafter, the liquid is poured out, the 
swollen polymer sample is weighed, and the weight of the original polymer 
sample (0.1 g) subtracted to obtain the weight of toluene in the swollen 
polymer sample. The swell index is calculated by dividing the weight of 
toluene in the swollen polymer sample by the weight of the original 
polymer sample (0.1 g). Therefore, a swell index is an indication of the 
amount of toluene taken up by the polymer sample. For instance, a swell 
index of 3 indicates that a polymer sample absorbed 3 times its weight of 
toluene. 
As crosslinkers for polycycloolefins, the polyfunctional cycloolefin 
crosslinkers are used in a relatively small amount for the purpose of 
curing or crosslinking the polymer structure of a polycycloolefin at an 
elevated temperature. Amount of the crosslinkers varies widely. For a 
crosslinker such as norbornadiene, amount varies from 0.005 to 0.5, 
preferably 0.01 to 0.2 moles of the crosslinker per mole of monomer 
charge. For crosslinkers having two or more norbornene groups, suitable 
amount thereof varies from 0.0001 to 0.1, preferably 0.0005 to 0.01 moles 
of the crosslinker per mole of the polycycloolefin. In addition to the 
catalyst, cocatalyst, temperature, and other variables, amount of the 
crosslinker affects molecular weight of the resulting polymer. Generally 
speaking, the more crosslinker used, the higher will be the molecular 
weight. 
It should be recalled that ring opening polymerization of cycloolefins 
containing a norbornene group results in a rupture of the ring and linear 
polymerization of the monomer. The linear structure of the polycycloolefin 
is characterized by the presence of unsaturation, which serves as the 
necessary sites for crosslinking. This system of crosslinking is unusual 
since crosslinking is accomplished in absence of free radicals, 
photoinitiators, or other initiators. Crosslinking herein is accomplished 
by polymerizing the polyfunctional cycloolefins with a cycloolefin monomer 
in a manner wherein the crosslinker functions as a comonomer, however, due 
to its multiple functionality, its polymerization is multidimensional, 
producing a crosslinked thermoset polymer. If the polymerization is 
carried out in absence of the crosslinker, a thermoplastic polymer is 
obtained which has a high degree of solubility in hydrocarbon solvents. 
Suitable polyfunctional crosslinkers include cycloolefins containing at 
least two norbornene groups each with one or more unsaturated sites. 
Suitable polyfunctional crosslinkers also include norbornadiene, which 
contains a bicyclo structure with two unsaturation sites. In a preferred 
embodiment, such polyfunctional crosslinkers include cycloolefins 
containing two or more norbornene groups and a total of two or more double 
bonds, and particularly such compounds in symmetrical structure. The 
preferred crosslinkers can also be defined more specifically as being 
selected from cycloolefin monomers having terminal or pendant norbornene 
groups with each norbornene group containing one double bond. 
Examples of specific crosslinkers for purposes herein include 
norbornadiene, tetracyclododecadiene, symmetrical cyclopentadiene trimer, 
reaction products of two moles of a cyclopentadiene with one mole of a 
diene, and the like. Preferred crosslinkers defined herein include 
norbornadiene, tetracyclododecadiene, symmetrical cyclopentadiene trimer, 
and symmetrical reaction products of two moles of a cyclopentadiene with 
one mole of a diene such as butadiene. Structural formulas of some of the 
preferred crosslinkers are given below to facilitate identification 
thereof: 
##STR1## 
In the symmetrical reaction products of cyclopentadiene with a diene, 
R.sup.1 is selected from alkyl groups of 0 to 50 carbon atoms, preferably 
0 to 10 carbon atoms; R.sup.2 and R.sup.3 are individually selected from 
hydrogen, alkyl and alkylene groups containing 0 to 50 carbon atoms, 
preferably R.sup.2 and R.sup.3 are individually selected from hydrogen and 
alkyl groups of 0 to 10 carbon atoms; and R.sup.2 and R.sup.3 can be 
combined to form a cyclic structure containing a total of 0 to 50 carbon 
atoms, preferably 0 to 10 carbon atoms. The crosslinkers are commercially 
available. 
As can be verified from the data in the appended examples, the preferred 
polyfunctional cycloolefin crosslinkers are those that contain two or more 
norbornene groups arranged symmetrically in the molecule and two or more 
unsaturation sites. Particularly preferred are those crosslinkers with two 
or more norbornene groups with the norbornene groups being in the terminal 
positions of a molecule and containing one double bond in each terminal 
norbornene group. This was verified in a number of different ways. In one 
approach, a small amount of dicyclopentadiene (DCPD) was used in the 
polymerization of methyltetracyclododecene (MTD) monomer employing the 
usual procedure. A polymer was obtained with a very high swelling index. 
This experiment was repeated but doubling the amount of DCPD used. The 
resulting polymer had, nevertheless, a very high swelling index, 
indicating ineffectiveness of DCPD as a crosslinker. 
It does not appear to be surprising that DCPD is relatively ineffective as 
a crosslinker for polycycloolefins. Since DCPD has the following 
structural formula, 
##STR2## 
it is evident that it lacks a second norbornene group with unsaturation. 
The double bond on the cyclopentene ring, in the above formula, does not 
appear to be as effective in the crosslinking reaction as the double bond 
on a norbornene ring in the corresponding position. 
The cycloolefin monomer, or a mixture thereof, can be polymerized with the 
crosslinker in solution or in bulk, in the presence of a suitable catalyst 
and cocatalyst, as well as other desired additives. In solution 
polymerization, a suitable solvent is employed together with a molecular 
weight modifier. Unless a proper proportion of the components is used, 
solution polymerization can lead to a mass of highly polymerized material 
of dubious utility. In bulk polymerization, principal parameters that 
affect molecular weight of the resulting polymer include reaction 
temperature, amount and particular catalyst and cocatalyst, and amount and 
particular crosslinker employed. Therefore, selection of a crosslinker and 
amount therefore should be carefully made and tailored to the desired 
polymer that is obtained. For instance, since tetracyclododecadiene is 
many times more effective as a crosslinker than is norbornadiene, a much 
smaller amount of tetracyclododecadiene need be used to obtain similar 
results. 
Bulk polymerization of a cycloolefin monomer containing a norbornene group 
can be conducted by adding the monomer and a polyfunctional cycloolefin 
crosslinker to a reactor maintained at room temperature. An antioxidant, 
such as a hindered phenol, can then be added to the reactor followed by a 
modifier compound, such as a bis(trialkyltin) oxide. This is followed by 
the addition of a metathesis catalyst system to the reactor, which 
includes a cocatalyst and a catalyst. There should be no reaction taking 
place at room temperature when the cocatalyst contains an alkoxy or an 
aryloxy moiety, however, on heating the reactor to an elevated 
temperature, the polymerization reaction is initiated with the crosslinker 
functioning in some respects as a copolymer by being copolymerized with 
the monomer. Due to the presence of polyfunctional moieties in the 
crosslinker, it also functions to crosslink the polymer structure to a 
thermoset condition. The reaction is completed in less than 10 minutes, 
preferably in less than 5 minutes, and the crosslinked thermoset polymer 
can be extracted from the reactor. As should be apparent, the reactor can 
be a mold which is pre-heated and maintained at an elevated temperature to 
expedite the process. 
The products obtained as described above, are of high molecular weight 
thermoset polymers which have dimensional stability and solvent 
resistance. Such products are useful in making automotive parts, 
electrical components, and the like. 
The norbornene-type monomers or cycloolefins that can be polymerized in 
accordance with the process described herein, are characterized by the 
presence of at least one of the following norbornene group, identified by 
formula I, that can be substituted or unsubstituted: 
##STR3## 
Pursuant to this definition, suitable norbornene-type monomers include 
substituted and unsubstituted norbornenes, dicyclopentadienes, 
dihydrodicyclopentadienes, trimers of cyclopentadiene, and 
tetracyclododecenes. Preferred monomers of the norbornene-type are those 
defined by the following formulas II, III and IV: 
##STR4## 
where R and R.sup.1 are independently selected from hydrogen, alkyl, and 
aryl groups of 1 to 20 carbon atoms, and saturated and unsaturated cyclic 
groups containing 3 to 12 carbon atoms formed by R and R.sup.1 together 
with the two ring carbon atoms connected thereto. In a preferred 
embodiment, R and R.sup.1 are independently selected from hydrogen and 
alkyl groups of 1 to 2 carbon atoms. Examples of preferred monomers 
referred to herein include dicyclopentadiene, tetracyclododecene, 
methyltetracyclododecene, hexacycloheptadecene, methyl 
hexacycloheptadecene, 2-norbornene and other norbornene monomers such as 
5-methyl-2-norbornene, 5,6-dimethyl-2-norbornene, 5-ethyl-2-norbornene, 
5-butyl-2-norbornene, 5-hexyl-2-norbornene, 5-octyl-2-norbornene, and 
5-dodecycl-2-norbornene. 
This invention especially contemplates preparation of homopolymers, 
copolymers and terpolymers of norbornene methylnorbornene, 
tetracyclododecene, methyltetracyclododecene, hexacycloheptadecene, methyl 
hexacycloheptadecene, and dicylopentadiene and especially homopolymers of 
methyltetracyclododecene and copolymers of methyltetracyclododecene and 
methylnorbornene. The copolymers of methyltetracyclododecene and 
methylnorbornene are polymerized from monomer mixtures containing from 1 
to 99% by weight methylnorbornene. The terpolymers are polymerized from 
monomer mixtures containing 1 to 99% by weight methylnorbornene and 1 to 
99% by weight methyltetracyclododecene, with the remainder being 
dicyclopentadiene or other bicycloolefins. 
The monomer or mixture of norbornene-type monomers can contain up to about 
20% by weight thereof of at least one other copolymerizable monomer. Such 
other copolymerizable monomers are preferably selected from mono- and 
dicycloolefins containing 4 to 12 carbon atoms, preferably 4 to 8 carbon 
atoms, examples of which include cyclobutene, cyclopentene, 
cyclopentadiene, cycloheptene, cyclooctene, 1,5-cyclooctadiene, 
cyclodecene, cyclododecene, cyclododecadiene, and cyclododecatriene. 
Any metathesis catalyst system can be used herein to conduct polymerization 
of cycloolefin monomers containing a norbornene group, a mixture of such 
cycloolefin monomers, or a mixture of at least one such cycloolefin with 
up to about 20% by weight of at least one other copolymerizable monomer, 
particularly cycloolefins of 4 to 12 carbon atoms which are devoid of a 
norbornene group. The use of a metathesis catalyst leads to ring opening 
polymerization of the cycloolefin monomers that contain a norbornene 
group. The metathesis catalyst system includes a catalyst and a 
cocatalyst. 
The catalyst useful herein is selected from ring-opening metathesis 
catalysts. In this type of polymerizations, the ring of the monomers is 
broken at one double bond to form linear polymers containing unsaturation. 
The metathesis catalysts include the molybdenum and tungsten halides, 
particularly molybdenum pentachloride and tungsten hexachloride, or 
variations thereof, used especially in solution polymerization. These 
catalysts are normally used in an organic medium, such as ethyl acetate 
and/or toluene, and these catalysts are unstable in air and and moisture. 
They react with air or moisture to form oxides or hydrogen chloride. In 
presence of oxygen or air, these compounds eventually oxidize to the 
respective oxides. Therefore, the halides of molydenum and tungsten should 
be handled in absence of air and moisture. 
The molybdenum and tungsten halides in the cycloolefin monomers start 
polymerizing the monomer even on standing at room temperature. A polymer 
begins to form after several hours of standing at room temperature, the 
polymer being an undesirable gel or a grainy mass of polymer in monomer. 
The metathesis catalysts also include the ammonium molybdates and 
tungstates described in Minchak U.S. Pat. No. 4,426,502. These catalysts 
are modified from the earlier version and can be handled at room 
temperature in a room environment, i.e., in the presence of air and 
moisture. These catalysts do not polymerize monomers but give stable 
catalyst solutions in the monomers. In a preferred embodiment, the 
ammonium molybdate and tungstate catalysts are used in a monomer solution 
to facilitate admixing the catalyst with the other ingredients of the 
polymerization system. Molybdenum (III) acetylacetonate or other organic 
soluble molybdenum or tungsten halogen-free compounds can be used as 
catalysts herein. 
The ammonium or organoammonium molybdates and tungstates suitable herein as 
catalysts are defined as follows: 
EQU [R.sub.4 N].sub.(2y-6x) M.sub.x O.sub.y 
EQU [R.sub.3.sup.1 NH].sub.(2y-6x) M.sub.x O.sub.y 
where O represents oxygen; M represents either molybdenum or tungsten; x 
and y represent the number of M and O atoms in the molecule based on the 
valence of +6 for molybdenum, +6 for tungsten, and -2 for oxygen; and the 
R and R.sup.1 radicals can be same or different and are selected from 
hydrogen, alkyl, and alkylene groups containing from 1 to 20 carbon atoms, 
and cycloaliphatic groups each containing from 5 to 16 carbon atoms. In a 
preferred embodiment, the R radicals are selected from alkyl groups each 
containing 1 to 18 carbon atoms wherein the sum of carbon atoms on all the 
R radicals is from 20 to 72, more preferably from 25 to 48. In a preferred 
embodiment, the R.sup.1 radicals are selected from alkyl groups each 
containing from 1 to 18 carbon atoms wherein the sum of carbon atoms on 
all of the R.sup.1 radicals is from 15 to 54, more preferably from 21 to 
42. 
The Minchak U.S. Pat. No. 4,426,502, referred to earlier, further defines 
the catalysts in instances where all or some of the R and R.sup.1 groups 
are same or different, which disclosure is incorporated as if fully set 
forth herein. 
Specific examples of suitable organoammonium molybdates and tungstates 
described herein include tridodecylammonium molybdates and tungstates, 
methyltricaprylammonium molybdates and tungstates, tri(tridecyl)ammonium 
molybdates and tungstates, and trioctylammonium molybdates and tungstates. 
U.S. Pat. No. 4,380,617 to Minchak et al discloses ring opening 
polymerization of a cycloolefin with a norbornene group in the presence of 
an alkylaluminum halide cocatalyst and an organoammonium molybdate or 
tungstate catalyst. 
U.S. Pat. No. 4,426,502 to Minchak describes bulk polymerization of 
cycloolefins using a modified cocatalyst with a catalyst whereby 
polymerization of the cycloolefin monomers can be conducted in absence of 
a solvent or a diluent. The alkylaluminum halide cocatalyst is modified by 
pre-reacting it with an alcohol or an active hydroxy-containing compound 
to form an alkoxyalkylaluminum halide or an aryloxyalkylaluminum halide 
which is then used in the polymerization reaction. The pre-reaction can be 
accomplished by using oxygen, an alcohol, or a phenol. As noted at bottom 
of column 4 of the Minchak patent, hindered phenols do not form the 
phenoxyaluminum groups and are relatively inert. The alkoxy or aryloxy 
group on the cocatalyst functions to inhibit the reducing power of the 
cocatalyst by replacing some of the alkyl groups on the aluminum. This 
makes it possible to first contact all the catalyst components at ambient 
temperature and to react cyclic olefins by means of bulk polymerization by 
thermal activation. 
It is important to lower the reducing power of the cocatalysts in order to 
make such bulk polymerization reactions practical. When an unmodified 
alkylaluminum cocatalyst is used with a catalyst to polymerize a 
cycloolefin, the reaction is very rapid. In such systems, polymerization 
in unacceptable since the active catalyst species are quickly encapsulated 
by polymer formed on contact between the cocatalyst, catalyst and monomer 
and is, therefore, not able to contact additional monomer present in the 
system for polymerization to continue. Mixing of the ingredients is 
accomplished by mixing the ingredients at room temperature without 
polymerization reaction or encapsulation. 
Towards the bottom of column 5 of the Minchak patent, it is stated that to 
be useful in bulk polymerization, the cocatalysts must contain at least 
some halogen, some alkoxy or aryloxy groups, and some alkyl groups, along 
with aluminum. As stated therein, when the cocatalyst is a 
trialkylaluminum, the polymerization product is a viscous cement wherein 
conversion of only up to about 30% is achieved even at a temperature as 
high as 140.degree. C. When the cocatalyst is aluminum trihalide or 
trialkoxyaluminum, very little or no desirable polymerization takes place. 
The use of aluminum trihalide is not recommended because of uncontrollable 
reaction leading to formation of a black, hard resin. Same is true of 
dialkoxyaluminum halide cocatalyst, since it does not contain any alkyl 
group. 
Contrary to the disclosure in the Minchak patent, a halogen-free cocatalyst 
can be used to polymerize norbornene-containing cycloolefins in the 
presence of a suitable metathesis catalyst. Such polymerizations are 
thermally initiated and are conducted at an elevated temperature of about 
50.degree. to 200.degree. C., preferably at 90.degree. to 150.degree. C. 
The system containing the catalyst and the cocatalyst is essentially inert 
at room temperature, which means that pot life is more than adequate at 
ambient conditions. However, the reaction takes place at elevated 
temperatures and can be completed in less than about one-half hour, 
preferably in less than one-fourth hour, and more preferably in less than 
about 5 minutes. If polymerization is conducted by reaction injection 
molding, polymerization is completed and a hard molded product can be 
extracted in less than 5 minutes when polymerization temperature in the 
range of 50.degree.-200.degree. C. is used. This, of course, depends on 
many variables, not the least of which is the thickness of the molded 
object. 
A halogen-free cocatalyst is disclosed in the related patent application 
entitled "Polymerization of Cycloolefins With Halogen-Free Cocatalysts" of 
inventors Minchak et al. That application discloses the use of an 
alkylaluminum, particularly trialkylaluminum, cocatalyst together with a 
modifier compound selected from alkyltin oxides, particularly bis(trialkyl 
tin) oxides. The polymerization is carried out in the presence of a 
catalyst and optionally, a hindered phenol. When the modifier compound is 
omitted, the system can be rendered operable by the use of a hindered 
phenol. Therefore, whenever a modifier compound selected from alkyltin 
oxides and sulfides is used, a hindered phenol is optional, however, if 
the modifier compound is omitted, the use of a hindered phenol is 
mandatory for an operable system. 
Suitable hindered phenols for purposes herein include those defined as 
follows: 
##STR5## 
where R groups are individually selected from alkyl groups of 1 to 6 
carbon atoms, and substituted and unsubstituted alicyclic groups of 4 to 8 
carbon atoms; and R.sup.1 groups, of which there can be 1 to 3 but 
preferably 1 or 2 such groups, are selected from hydrogen, alkyl groups of 
1 to 12, preferably 2 to 8 carbon atoms, and substituted and unsubstituted 
alicyclic groups of 4 to 8 carbon atoms. In a preferred embodiment, R 
groups are tertiary alkyl groups, particularly t-butyl groups. There is 
one R.sup.1 group in a preferred embodiment at the 4-position which is 
selected from alkyl groups, preferably lower alkyl groups, such as butyl. 
The catalyst in the polymerization systems disclosed herein is employed at 
a level of about 0.01 to 50, preferably 0.1 to 10, millimoles per mole of 
monomer charge. The molar range of cocatalyst to catalyst can vary widely 
over the range of 200:1 to 1:10, preferably 10:1 to 2:1, of aluminum to 
molybdenum or tungsten. The molar ratio of the modifier compound to 
aluminum in the cocatalyst is in the range of 0.1 to 3, preferably 0.5 to 
2, and especially about 1.25 moles of modifier compound per mole of 
aluminum. The amount of hindered phenol can be in the range of 0.0001 to 
0.01, preferably 0.001 to 0.5 moles of the hindered phenol as moles of 
hydroxyl (OH) per mole of monomer charge. Per one mole of aluminum in the 
cocatalyst, amount of the hindered phenol is about 0.1-20 moles, 
preferably 1-10 moles as hydroxyl (OH). 
In cases where polyfunctional cycloolefin crosslinkers are used, the 
resulting polymers are solvent resistant, crosslinked, thermoset products 
which can be elastomers or plastic, depending on Tg thereof.

The following examples demonstrate effectiveness of the herein-described 
polyfunctional cycloolefins as crosslinkers in the polymerization of 
cycloolefins containing at least one norbornene group. 
A small amount of carbon tetrachloride was used in some of the examples 
that follow. This was done pursuant to the disclosure of Hercules U.S. 
Pat. No. 4,481,344, which teaches that the use of a small amount of a 
labile halide, such as in carbon tetrachloride, would yield high 
conversions on the order of 99.9%. The results in the following examples 
did not verify the teachings in the Hercules patent, possibly due to the 
fact that a somewhat different system was used herein. However, the minute 
amount of carbon tetrachloride is believed not to have affected the 
invention disclosed herein. Polydimethylsiloxane used in the examples 
functioned to protect the surface of the plaques that were produced. The 
antioxidants used were hindered phenols. 
EXAMPLE 1 
This example demonstrates polymerization of methyltetracyclododecene (MTD) 
in presence of metathesis catalyst system but in the absence of a 
crosslinker. Since this system is devoid of a crosslinker, this example is 
not illustrative of the invention disclosed herein. 
The following materials were used in the polymerization of the MTD 
cycloolefin monomer: 
50 mls MTD (48.5 grams or 0.279 mole) 
1.0 g Ethyl 330 hindered phenol antioxidant 
0.05 g polydimethylsiloxane 
0.5 ml carbon tetrachloride (0.73 g) 
2.8 ml of 0.5M propanol-1 soln in MTD (2.73 g or 1.25 millimole) 
2.0 ml of 0.5M soln of diethylaluminum chloride in MTD (2.1 g or 1.0 
millimole Al) 
2.0 ml of 0.1M soln of tetrakis[tri(tridecyl)ammonium]octamolybdate (1.9 g 
or 0.01 millimole Mo) 
In carrying out the polymerization reaction, the MTD monomer was added to a 
reaction vessel maintained at room temperature, which vessel was pre-dried 
and flushed with nitrogen before use. Then, the antioxidant, the siloxane, 
carbon tetrachloride, the propanol solution and the diethylaluminum 
chloride catalyst solution were added to the vessel with agitation after 
addition of each ingredient. After the ingredients were added and 
agitated, the reaction vessel was placed under a vacuum for 5 minutes and 
the vacuum was then broken with nitrogen to provide an inert atmosphere in 
the reaction vessel. Finally, the organoammonium catalyst solution was 
added to the reaction vessel which was then again evacuated for 1 minute 
and the vacuum was again broken with nitrogen. 
The contents of the reaction vessel were transferred under a slight 
pressure to a mold pre-heated to 80.degree. C. The reaction exothermed in 
the mold to a peak of 210.degree. C. The plaque which was formed in the 
mold was left in the mold for 10 minutes after reaching the temperature 
peak to allow the material to cool down to mold temperature, and then was 
removed. 
The plaque was greenish-yellow in color with distinct areas of dark green 
color. The dark green areas apparently resulted from the presence of 
carbon tetrachloride. A rigid plaque was obtained in about 1.2 minutes 
from the time the monomer charge was transferred into the mold. The plaque 
weighted 44.93 grams and the monomer conversion was 92%, as determined by 
TGA analysis. The swelling index (SI) of the plaque sample was 46.0, 
indicating a very high absorption of toluene by the sample and conversely, 
a very low degree of crosslinking. 
EXAMPLE 2 
This example is similar to Example 1 with the principal exception of using 
norbornadiene as the crosslinker, as described herein. This example, 
therefore, is illustrative of the invention disclosed herein. 
Again, the following materials were added to a reaction vessel maintained 
at room temperature: 
50 ml MTD 
1.0 g Ethyl 330 hindered phenol antioxidant 
0.05 g polydimethylsiloxane 
2.0 ml neat norbornadiene (1.85 g or 0.020 mole) 
0.5 ml carbon tetrachloride 
2.5 ml propanol-1 soln (2.5 g or 1.25 m moles) 
2.0 ml Et.sub.2 AlCl cocatalyst soln 
2.0 ml molybdate catalyst solution 
The same materials in the same amounts were used here as in Example 1 with 
the exception of using the norbornadiene crosslinker which was added to 
the reaction vessel following the siloxane. After adding all of the above 
ingredients except the catalyst solution, the reaction vessel was 
evacuated for 7 minutes and the vacuum was broken with nitrogen. Then, the 
molybdate catalyst solution was added and the reaction vessel was again 
evacuated for 4 minutes and the vacuum was broken with nitrogen. 
The mold at 80.degree. C. was charged from the reaction vessel. The 
reaction in the mold ethothermed to 210.degree. C. The plaque was left in 
the mold for 20 minutes after the temperature peak was reached and then 
removed. A rigid plaque was formed in the mold in about 1.0 minutes from 
the time of charging the mold. 
The plaque was characterized by large areas of dark green to black color 
but the edges were clear. It weighted 47.43 g. Conversion to the polymer 
was 92.5%. Sample of this plaque had a swelling index of 9.3, indicating a 
substantial degree of crosslinking. 
EXAMPLE 3 
This example demonstrates preparation of crosslinked or thermosetting MTD 
using dicyclopentadiene (DCPD) trimer as the crosslinker. This trimer 
consisted of 5% by weight of symmetrical and 95% by weight of 
unsymmetrical trimer. Since the unsymmetrical trimer is considered to be 
much less effective as a crosslinker than the symmetrical trimer, it can 
be assumed herein that only 5% of the trimer used was effective as a 
crosslinker. This example is illustrative of the invention disclosed 
herein. 
The same procedure was used herein to polymerize MTD using the following 
materials: 
50 ml MTD 
1.0 g Ethyl 330 antioxidant 
0.05 g polydimethysiloxane 
2.0 ml neat DCPD mixed trimer (2.17 g or 0.011 mole) 
2.4 ml propanol-1 soln (2.39 g or 1.2 m mole) 
2.0 ml Et.sub.2 AlCl cocatalyst soln 
2.0 ml molybdate catalyst soln 
The plaque removed from the mold was rigid and weight 52.547 g. It was 
formed in 1.0 minutes from the time of charging the mold. Monomer 
conversion was 93.1% and the swelling index of the plaque sample was 3.9, 
indicating a high degree of crosslinking. 
Since there was only 5% of the symmetrical trimer in the trimer mixture, 
only 5% of the 2.0 mls was effective as a crosslinker, or 0.00055 mole. 
The minute amount of the crosslinker and the high degree of crosslinking 
obtained, shows the superb effectiveness of the symmetrical trimer as a 
crosslinker. 
EXAMPLE 4 
This example demonstrates the use of tetracyclododecadiene as the 
crosslinker and is therefore, illustrative of the invention described 
herein. 
The same procedure was used as in previous example using the following 
materials: 
50 mls MTD 
1.0 g Ethyl 774 hindered phenol antioxidant 
0.05 g polydimethylsiloxane 
0.2 ml neat tetracyclododecadiene (0.21 g or 0.001 moles) 
2.4 mls propanol-1 soln (2.4 g or 1.2 m mole) 
2.0 mls Et.sub.2 AlCl cocatalyst soln 
2.0 mls molybdate catalyst soln 
The plaque was removed from the mold weighing 45.92 g, and it was rigid. 
The plaque was formed in 0.6 minutes after the mold was charged. There was 
evidence of lines or voids in the plaque. Monomer conversion was 95% and 
the swelling index of the plaque sample was an excellent 2.1. 
EXAMPLE 5 
This example also demonstrates the use of tetracyclododecadiene as a 
crosslinker, as does Example 4, above, however, amount of the crosslinker 
was one-half of that used in Example 4 and the cocatalyst used here was 
triethylaluminum with bis(tri-n-butyltin)oxide, whereas the cocatalyst in 
Example 4 was diethylaluminum chloride. This example is illustrative of 
the invention disclosed herein. 
The same procedure was used here as in the preceding example using the 
following materials: 
50 mls MTD 
1.0 g Ethyl 774 hindered phenol antioxidant 
0.05 g polydimethylsiloxane 
0.1 ml neat tetracyclododecadiene 
0.3 ml neat bis(tri-n-butyltin)oxide (0.35 g or 1.2 m mole Sn) 
2.0 ml triethylaluminum cocatalyst 0.5M soln (2.0 g or 1 m mole Al) 
4.0 ml molybdate catalyst soln 
The plaque was removed and weighted 45.81 g. It was rigid and was formed in 
1.7 minutes after charging the mold. Monomer conversion was 90% and the 
swelling index for the plaque sample was an excellent 3.0. 
EXAMPLE 5 
Example 4 was repeated with one exception: whereas 0.2 ml of the 
tetracyclododecadiene crosslinker solution was used in Example 4, 2.0 ml 
of the same crosslinker solution was used herein. 
Following the same procedure and using the same materials, a rigid plaque 
was obtained in 0.8 minutes with the following relevant data: 
Monomer conversion--95% 
swelling index--1.3 
This example demonstrates that a higher degree of crosslinking can be 
achieved by using a higher level of crosslinker.